Does anyone have a clue what this is?

[Gladteeth]

Went to the dentist today for my son's check up and they found a little growth at the bottom of mouth. They've told me not to worry but they had two other dentists come in and look at it and they've booked him back for another check up in 2 weeks!!

 

[Zuri Barniv]

It is standard to wait two weeks after seeing anything atypical in the mouth to make sure it disappears. That doesn't mean it is anything bad. By the teeth, it looks like your son is around 8yrs old or so? It would be extremely unusual to have anything serious going on under the tongue and it will probably be gone when they check it again in two weeks. It is most likely an injury from food like a sharp tortilla chip, etc.