All were negative. I also have geographic tongue. You say that if you get aphthous ulcers and they go away before 14 days by themselves then you are not immunosuppressed. Apthous ulcers are small, painful, and shallow sores that can appear white or gray surrounded by a red halo. Anywhere from two to fifteen ulcers can appear at one time and can individually last up to two weeks.
Some people experience new canker sores in succession for up to one month.
Several episodes a year are not uncommon. Canker sores can be very painful and may interfere with eating, drinking, and speaking. Stress and anxiety, mouth trauma, food allergies, gastrointestinal problems, immune suppression, and viral or bacterial infections have all been suggested as causes. Many people start getting them when they are coming down with a cold or the flu. There is no cure for canker sores but there are some suggestions to reduce the pain and possibly the sores' duration.