Most aphthous ulcers go away on their own after one or two weeks.
Symptom
Most wounds are round or ovate with a white or yellow centre and a red border. They form in the mouth, on or under the tongue, on the cheeks or lips, at the base of the gums or on the soft palate. You may notice a tingling or burning sensation a day or two before the actual appearance of the wounds.
There are several types of chakra wounds, including smaller, larger and herpetic wounds.
Small ulcers
The smallest ulcers are the most common and:
They are usually small
They are oval with a red border.
Heal without scars in one or two weeks
Older ulcers in the mouth.
Major aphthous ulcers are rarer and:
They are larger and deeper than smaller cancers.
They are usually round with defined limits but may have irregular edges when they are very large
It can be very painful
The healing can last up to six weeks and can leave extensive scars.
Mudra For Aphthous ulcers
According to Ayurveda, this condition is caused due to Vata vitiation and also due to weak immunity. The practice of Prithvi mudra and Pran mudra helps to suppress the excess Vata and also empowers health and vitality.
Prithvi mudra

How to do Prithvi mudra.
Join the tips of the ring finger and thumb finger to for Prithvi mudra.
Pran Mudra

How to do Pran mudra
Join the tips of the ring finger, little finger and thumb finger to form Pran mudra.
Duration of mudra practice
45 minutes of regular practice or 15 minutes thrice a day
You have to do mudras with both the hands. Just a simple touch of the tips of fingers is enough to get results of mudra practice.
Precautions
If you are a Kapha excess person, then do these mudras in moderation only.
The video of Mudra For Aphthous ulcers
I think this mudra is helpful for you.Also, read my book "Complete Hand Mudras." It will give you more information about mudras read more