2 year old has a white pimple on jaw under tongue. has cold/cough now and has been scratching around his neck and back of legs. what is this pimple?

MD and DDS: First have your child seen by your pediatrician or family physician, who can evaluate the entire situation. If your physician feels that he\she should also be seen by a pedodontist (pediatric dentist), that would be a good idea also. I hope your child has already been seen by one, which is recommended by this time anyway. We can't diagnose the pimple without actually seeing it.

Absess/bone: Your description could be an abcess in the bone or gums. If it is hard it could be a bony spicule. Time to head out to a dentist to make sure!