Hello,
From what you have specified it seems to be aphthous ulcers.
Aphthous ulcers are ulcers formed due to stress; vitamin b12 deficiency is also associated. Ulcers are erosions of mucosal layer in mouth.
The stress factor in your case could be a wisdom tooth growing, which is rubbing against the mucosal layer causing friction and therefore resulting in ulcer. You should first look into your wisdom tooth; if it's causing trouble you can remove them. Secondly, you need to take supplements of vitamins, would prefer you to have lots of green leafy vegetables and fruits.
You can use topical anesthetic agent on ulcer before eating, like half an hour before. So that will give you relief while eating. You can use saline gargle; it will remove the micro organisms. Do not have anything spicy.
Thank you.