You say that you've "been following Dr. Dancebelt's instuctions for sometime now" but that you just got a bout of pain in your balls.  Did you do anything different from usual, like maybe handle yourself roughly when you were putting yourself into position in the dancebelt?  Have you ever felt this pain before?

Couple other questions:  Is your dancebelt maybe too small?  How about your tights?  If you don't have the right sizes, you might be pinching your balls or putting too much pressure on your scrotum.  

Finally, if you were happy to wear regular underwear for two years while dancing and nothing bad ever happened, why change?  If you are on a professional track as a dance student or if you ever appear in an actual ballet, then you'd have to wear a dancebelt, but if not, you should do what's proven to work for you, and don't worry about upsetting Dr. Dancebelt.  He can take it, I'm sure.