"The meticulously placed masses of skin under her eyes were captured involuntarily by the customary light fixtures of the hospital ward, sufficiently polluted with the indistinct clamour of her deranged relatives."
I found the sentence hard to read. I do not think that the problem is so much awkward grammar as it is excessive cognitive load. The sentence as written requires the reader to hold quite a number of concepts in their mind until the end of the sentence in order to understand it. There does not seem to be any rhythmic structure such as parallelism to organize the concepts. So, not a shining example.
What to do to fix it?
The first question is what is the purpose of the sentence. It appears to be descriptive but I am not at all sure. So the first step on the road to excellence is to clarify the purpose of the sentence. Only you can do that.
The second question is how to accomplish that purpose. You can pick a point of view, a narrator, the distance of the narrator from the story, the language and vocabulary used, the velocity of the text, the expected cognitive load, and so much more.
So who is telling this story? Are they telling the story as it unfolds or recounting past events? Is the narrator a player in the story or some form of historian? Are they low-brow or high-brow in the sense of the language that they use? Do they typically express their thought in long sentences, short sentences, mixed and varied sentences, or grunts? What is the expected level of cleverness of the readers?
My sense is that you are a beginning writer. What I would suggest to a beginning writer is to experiment with different approaches to the scene from which this sample sentence is taken. Pick a POV, a narrator, and so on. Write the corresponding scene. Make different picks and write again. None of these have to be polished, ready to publish scenes. You do not even have to finish a given scene; if it is not working, then it is not worth the effort to finish. When you have a handful or two of these scenes, pull out the trusty compare-and-contrast analysis tool. Enumerate the good and bad aspects of each scene. At some point you will recognize that one set of options works better than any of the other options.
To be fair, you might have to do this kind of analysis for each scene in your work.
Just from a 'craft' perspective, the difficulty I have with this sentence is that it uses too many adjectives and some unconventional word choices, and that makes it difficult to visualize what's actually happening. For instance:
The meticulously placed masses of skin under her eyes [...]
I assume that means something in context, but I can't visualize it, in part because no one talks about 'masses' of skin (excepting the context of cancer). A piece of shin, a skin-graft, sure, but a 'mass' conjures up a big lump of flesh, which is a weird image. 'Carefully' would work better than 'meticulously' as well, unless you have a reason to use the less common, fussier adjective. And then this:
[...] were captured involuntarily by the customary light fixtures of the hospital ward
'Captured' is too active a word, particularly when combined with he word 'masses'; it sounds like something grabbed the lumps of flesh under her eyes. And it's not at all clear what 'involuntarily' means in this context. Whose action is involuntary? The light fixtures'? Anyone reading this will come to a dead stop at this point trying torahs out the references.
You should also allow readers to use their own experience to set the scene: Instead of 'customary light fixtures of the hospital ward' just say 'lights of the hospital ward' Readers know what hospital ward lights look like; they know what's customary, and you don't need to tell them to imagine that. You could be more specific to set the scene more carefully — e.g., use 'lamps' instead of 'lights' to give it an old-time feel, or 'fluorescent bulbs' to make it harsher and more clinical — but 'customary' and 'fixtures' don't add anything to the sentence except more syllables.
The last phrase:
sufficiently polluted with the indistinct clamour of her deranged relatives
is overdrawn. First, 'sufficiently' is the wrong word, I think; it means 'enough', but what does 'polluted enough' mean in this context? Second, you're mixing a visual image with an aural image (hospital light polluted with indistinct clamor), without creating an explicit metaphor (e.g., "as though the light in the room was polluted by their clamoring"), Third, you've packed at least three separate ideas into this single, short phrase: the idea that the light is tinged by the sounds; the idea that there are relatives in the room speaking indistinctly; the idea that the relatives are themselves deranged. That's too textually dense to make for pleasant reading.
I'd suggest you take the sentence, strip out all the unnecessary adjectives, break it into all the separate ideas you're trying to convey, and then rewrite it as a full paragraph, developing each idea on its own. You can add adjectives back in to give 'color' as you see fit, but start with a simple, clear version and work up.
It feels to me like you're rushing through the description to get to the story, but the story likely won't work unless you take the proper time to develop the scene.