回复：两岁女儿的舌头后根少了一下片舌苔, 请问是怎么回事啊?

Sounds like Geographic Tongue, aka. Benign Migratory Glossitis. It's a condition of unknown cause and don't worry, the patch may actually "migrate" around yet you don't have to do anything except for the checkup with your daughter's dentist.

Take care.