Suggest Remedy For Painful Boil In Armpit

hi, i am currently on 125mg of lexvothyroxine daily and have been on this drug since birth i just wondered what are the side effects of this drug...are boils common? I have had a boil in my armpit for the last 3 days which is very inflamed and painful, any tips to get rid of it would be much appreciated. many thanks Aimee