hi i had gone through your query and understand your concerns. i would come up with two most possibilities to fit your condition .these include
1.first possibility is,APTHOUS MOUTH
possible causes include;
-Stress or tissue injury is thought to be the cause of simple mouth ulcers.
-Certain foods, including citrus or acidic fruits and vegetables (such as lemons, oranges, pineapples, apples, figs, tomatoes and strawberries), can trigger a mouth ulcer or make the problem worse.
- nutritional problems, such as vitamin B-12, zinc,
folic acid, or
iron deficiency and gastrointestinal tract disease, such as
Coeliac disease and Crohn's disease are the other causes
2.second possibility for armpit lump is,
FURUNCULOSIS ;
possible causes
-maceration of skin,dusty,dirty environment,and ingestion of too many carbohydrates may predispose to furunculosis.
treatment option;
i advise you taking
Homeopathic medicines gives safe and permanent cure for your complaints
consult your local homeopathic physician for correct diagnosis of the case and remedy to fit your complaints
I hope this is helpful for you, thank you