Hydrogen peroxide 3% is more for antiseptic rinse purpose, the ingredients in mouth wash is more for antigingivtis and antiplaqe to get rid off those dirty build up bacteria organisms,both are pretty handy even for human like us too
So I've been keeping the area clean and cutting the pointed legs from my roaches and crickets, even been feeding him silkworms for quite a while now and it hasn't gotten better or worse until I noticed something today. In person it looks like a separation of the top and bottom lip instead of closed together. I think he'll need to have a vet visit.