I really don't think pouring hydrogen peroxide on your tongue can be a good idea!
But, in answer to your question, over the past 11 months of TX I've read dozens of posts from TX'ers with mouth sores
A lot of people recommend 'Magic mouth
Wash." (Will someone please chime in and post what that is?)
I've not suffered from inner mouth sores
but have had really irritating corner-of-the mouth
cracking that sometimes prevented me from brushing my teeth or even eating much. My Dr.