I had a reoccuring cyst on my back come to a head and pop, but its still hard and slightly painful. what should i put on it?

Removal: If it is recurring it is likely something that needs drainage and pssible removal to avoid its recurrence. Depending on its size you may need to see a surgeon to have it taken care of properly.

Sebacious cyst: This is likely a sebacious cyst and can usually be excised in your family doctor's office. While you can get rid of the infection temporarily it'll most likely recur without removing it.

Use warm soaks : Use warm soaks and if still no better see your doctor.