Hi DrSir,Im 29 years male. 68kgs. I found that small lump of 5mm diameter (since 5 months) and blackish exactly middle of backbone (backside). size and color is not changing. its not paining also.   I consulted my family physician. They told that, this is cyst and will need surgery to remove.  so until it doesn;t give any problem (like pus or pain), I can ignore that..   somehow, they said no medicines needed  in this case.. hence thought of checking..
His appreciate your concernLooking at your symptoms it could be sebaceous cyst no medicine is required for it until it gets infected please visit your doctor for surgical removal that is the only option Hope I have answered your question thanks for using ChatDoctorgood luck