I Think I've Had A Little Cyst On My Scrotum

I think I've had a little cyst on my scrotum for about 5-6 years.. Gradually kept getting bigger, swollen until a few days ago I feel another one kind of growing off of it.. 2 days later wham its blown up to the size of a golf ball, tight and hurting to the touch. Infected obviously but is it definitely a cyst ? Could it possibly be a std? It kinda of popped tonite and is leaking out smelly white yellowish pus that won't stop coming out. What do you think the problem is?