Well one day at night I came in to check my betta fishes and one while checking I think spooked one my fishes and he started to thrash in the water and he got a mark in his Gill area where they use it to Flare..He was a very very active fish but now he's not eating but he is moving well but he's just too scared of Mee now and not active at all like before....this happened a week ago and I thought he would be ok. He usually flares with the gills but now he can't open one of them.....
He's just stressed out from something. What are the tank parameters? Check for a spike in ammonia or nitrates, that could very well be the problem right there. I would do a big water change immediately just to be on the safe side, then give him a day or so and try feeding then.
I'm I reading this post correctly... he said he scared his fish and he ran into something and has obvious physical injury. This isn't from parameters in the tank.
Normally, Melafix is recommended, but betta's can't handle Melafix (or I think Primafix). Daily water changes may be your best bet. Or a bath in Methylene blue may be called for.. it looks kinda bad. Although, your water does look cloudy so it's likely not helping.