Hi, YG!
Good news I think - DS2 fell off his bike onto his chin a few months ago and was left with a large hole, which the treatment room nurse fixed with steristrips.
After it healed he was left with quite a big lump under his chin, which I assumed was permanent, but I just checked his chin and there is nothing there now!
(I took a pic at the time so hang on and I will see how long ago it was)