Thanks for writing to us.
The described lesion could have been a boil/furuncle
or sebaceous cyst
Right now just do warm water compresses of the drained lesion and apply antibacterial cream like bactroban
. A boil would resolve with this treatment, if its a sebaceous cyst it would recur again after sometime. Sebaceous cyst is treated by excision of the cyst. But right now to prevent any further infection you need to follow the treatment prescribed above
Hope that helped