A few things come to mind at first glance... is the violet in a pot with drainage holes? I can only see the glazed container from here, and that will certainly cause root rot and root death over a rather short period of time.

The leaves look very irritated by something, but I don't think by a pest. Sunburn and fertilizer burn come to mind. Most beginners--me included--give their violets direct sunlight, and not bright light. Similarly, they often follow fertilizer package instructions, which is usually too strong for AVs.

The best course at this point, either way, would be to take a healthy leaf and propagate new ones. It's possible for the plant to recover, but since it only has a few good leaves in the center, it might be difficult for the plant. If it has been in a waterlogged pot, then taking a leaf is definitely the fairest option for the plant. :o)

Birthmarks. May be sporting, may be not. Not a problem.

Thanks guys, the other three I gave her are perfectly fine, same treatment and flowering beautifully. I will tell her to just hang tight.

Ohhhh. I didn't know that was a thing! Sorry about that. I'm glad it's fine!

If its a sport and turns out really neat I may want it back! Hah

It can be quite unstable. Or darker.