To describe the same situation without まま, you would say:
There is nothing wrong with this sentence. As you say, we can tell from まだ that the nose was in the same state earlier. However, it doesn’t quite say it has remained that way all this time. It’s more like a snapshot of the current state with a hint that it was like that earlier, too.
まま makes it explicit that the nose has been left in that state. So much so that I feel the following sentence with まま but without まだ is closer to the original sentence with both in it than the sentence above without まま is to either.
So if anything is redundant, it would be まだ, which is an adverb after all. An aspect marker is more powerful than an adverb in describing an aspect. But まだ serves the function of adding emphasis as a good adverb.