I have 2 problems I am trying to fix......

[fantrombone]

I have 2 problems I am trying to fix. But will only state one here. After playing for serveral hours, I get sores (not open ones) on the inside of my lower lip. I have tried playing PP, shifting my embrochure, staying in the low and middle range, but I still get them. Sometimes it hurts like hell. Any suggestions or advice?

[hyperbolica]

Teeth? Your lip might be riding the edge of your teeth.

[Doug Elliott]

I'd have to see you play to give any valid advice.
There are several possible issues and they're probably closely related to whatever the other problem is.