Hi D.D. and welcome!
I am sorry to hear of this issue and the worry it is causing you currently.
First of all, you are going to be alright...this is not something that puts you in immediate danger...
...however, it does sound as if you should be seen by your doctor in order to clear up the infection from the boil/cyst/abscess. (hard to say exactly what it may be)
You'll likely have it drained, and follow up with some antibiotics, and be completely rid of the problem in no time.
Don't be scared, just make an appointment and get it looked at as soon as possible.
Be well, and let us know how you are doing soon.
"Courage is not the abscence of fear, it is feeling afraid and doing it anyway!"
"Worrying does not empty tomorrow of its troubles...it empties today of its strength."
Corrie Ten Boom
Panic Syndrome recovery due to CBT