For adults you may find applying tea tree oil with a qtip a couple times a day can speed healing.
It stings but is effective. Also homeopathic rhus tox 2-3 times a day can help with mouth ulcers. If it is trauma from biting your gum, these two suggestions may not help as much. Swish and spit with mouth wash and peroxide (50/50) can also be helpful.(also stings a bit).