There are several reasons for the painful blisters on the child’s tongue: 1. When the incisive end of the newly erupted lower front teeth is sharp, there are residual roots and crowns in the dental row or the lingual tether is too short, the lingual mucosa is repeatedly stimulated to form blisters that can break down and produce ulcers. 2. When herpes simplex virus infection triggers herpetic stomatitis, dense clusters of small blisters, the size of a pinhead, can form on the tongue and lip and cheek mucosa, etc., and break down to produce superficial ulcers. When herpes stomatitis is present, small round blisters can form on the throat and tongue, causing redness and pain in the mucosa. 4. When a child drinks hot water or eats food that is too hot, the mucous membrane of the tongue burns and produces more blisters with oozing.