Thank you for the query.
) usually has nothing to do with an infection. Especially if is painless. The cyst is usually filled with clear, not infected fluid. You can put a flashlight to it and see if it passes the light. If so, the clear fluid is inside. And that means no infection is present.
So antibiotics wont help with it at all.
You should rather have an ultrasound
of your testis, to rule out other things (like a cancer). And if this is only a cyst, and does not grow, it can be left alone. If it grows and gives you discomfort, it can be surgically incised so the fluid will be drained.
Hope this will help.