Red Stuff in Betta's mouth?

I've had a crowntail male betta for about 7 months now. We are currently using Tetra LifeGuard to treat a fungal infection he had, but then we noticed there was like, red stuff in and around his mouth. He hasn't been eating, so we think that with the red stuff in his mouth its preventing him from eating. Help! Does anyone know what this is or how to treat it? QUICKLY! THANKS!