How To Treat A Cyst On Left Shoulder?

I am 20 yrs. old, female, 5'0" and weighing 50 kgs..I have a cyst on my left shoulder since i was a kid it really doesn't hurt at all but i am worried because its getting bigger.What I must do with this?I also have acne scar problems and I can't stop to eat sweet foods like chocolates or any sweets in a day.How can i solve this problems of mine?