Is there a cure for priapism?

Yes. Ischemic or low flow priapism is treated by aspirating stagnant blood from penile rods, then neosynephrine (phenylephrine) is injected into penile rods. This can be repeated. Penile shunt surgery, creating a window between corporal dods and urethral spongeous tissue maybe required if medication unsuccessful. Rarer high flow piiapism can resolve on its own or at worst require injection of blood clot to slow flow.
Yes. If you have priapism and it's been more than 6 hrs you will probably need surgery to get your erections back.