A small hole in a baby tooth hurts when touched, which may be caused by deep caries, apical inflammation, impending tooth replacement, low pain threshold, etc. It is recommended to go to the hospital for specific examination and treatment. 1. Small holes in milk teeth will have irritation pain if they are damaged to the dentin layer, and the pain is usually not persistent. 2. Due to the rapid progress of dental caries in milk teeth may appear from the surface of the small hole, in fact, the root tip has been inflamed, when there is contact will produce pain. 3. Permanent teeth are about to erupt, the milk teeth have small holes, but about to fall out, the teeth will be loosened when touched pain. 4. The child’s pain threshold is relatively low, know that there is a hole or a little feeling also feel pain, is also possible, it is recommended to repair in time.