Do not attempt to rupture the cyst. If it's contaminated, you risk spreading the illness, and if the sac is left beneath the skin, it might grow back. Your doctor can tell you how to take care of yourself after an injury, and if necessary, provide protective clothing or other medical equipment that will help prevent further contamination. The only way to know for sure whether the skin is healthy enough to support a piercing is to test it first. If the area around the cyst feels warm to the touch, is red or swollen, then the skin is probably not healthy enough for a piercing. You should also wait until the wound has healed before trying again. The opening in your skin may still be too large to safely pass a needle through. You should also wait until any remaining fluid in the sac has disappeared before starting work on another hole. Cysts are usually caused by bacteria invading through a break in the skin, often following a scrape or cut. The bacteria accumulate inside the body's sweat glands and cause them to malfunction, leading to the formation of cysts. The only way to treat a cyst is to remove the dead tissue around it.