Hello and welcome to Healthcare Magic. Thanks for your query.
It appears that you are quite stressed out about the bump which you have noticed recently. The bump which you are describing is probably a sebaceous cyst. This is a not a serious problem and you don't have to be stressed out so much because of this and it is common to have sebaceous cysts in sweaty areas like the groin area / testicles. The recent increase in size, tenderness and pointing indicate that it has gotten infected.
The infected cyst
will most likely to break open on its own and discharge the pus. Don't pinch or squeeze the swelling. Keep the area clean (you can wash it with a gentle soap) and dry as far as possible. If the pain is more, then you can take a mild anti-inflamatory medication for reducing the pain and inflamation.
If you develop fever
or any other complications or a recurrence of the swelling, then you should see a doctor.
Wish you all the best.
Dr. Jonas Sundarakumar