I did a little search on Google (my best friend online lol) and although there is no direct connection to sores they mention the connection of dry mouth and ulcerations. Adderall can cause dry mouth in many which can lead to gum disease, sore or bleeding gums and canker sores.
Perhaps try lozenges, candy or something else to keep the saliva flowing. Maybe check with your doc as well on the possibility of scurvy (yes people get that still) as one of the symptoms is shrinking gums. We cannot take vitamin C with our meds at the same time and often we miss out on it. Vitamin C deficiency can damage gum tissue and this time of year we tend to miss out on it. It could be as simple as having more citrus in your diet!