My daughter is 5 months old and teething. Since yesterday she had been crying a lot and rejecting the breast. I looked inside her mouth and was shocked to discover that she had a red soreness under her tongue. I tried to look it up on the internet but I c

Sores in mouth. Hi, sorry you are having problems with your infant. Sores in her mouth could be a virus. There is one that causes hand/foot/mouth lesions. But I would have her checked by her doctor to look inside her mouth and to be sure she is staying hydrated.