How Can You Tell The Difference Between Warts And Sebaceous

How can you tell the difference between warts and sebaceous cysts on your scrotem ?? I have had a huge white hard bump on the underside of my scrotem ...I left it alone and it disappeared but I now have another two white smaller bumps ...how can I treat this if it is a sebaceous cyst problem or how can I tell the difference if it's a wart or not ??