Strange injury to thumb: Advice / Feedback needed

Hi, Pleased to be here,

This is my first post and wish it was under better circumstances. I'm concerned about a painful injury I sustained while trying out a new technique. I talking about the body slapping and tapping like I've seen done by players like Jimmy Whalsteen & Andy McKee. Anyway, I haven't seen any specific instruction on how to do this so I just waded right in and have been experimenting with a few techniques. What I was trying was hitting a chord, coming off with the left hand and doing a side body slap, followed by finger taps on the pick guard, then coming up above the strings to do a body thump abuve the sound hole  for the low end tone and putting my hand in position  to strum again.

Well, I found a particular rhythm and sequence I liked and practiced it for about five minutes. I stopped playing for awhile to do a few other things and a few hours later I started feeling a pain in ball of my right thumb. A few hours later, it was so painful, I couldn't even touch it without wanting to scream. I looked at the thumb under high magnification and could see no problem. Two weeks later, (still not being able to hold a pick without pain), I noticed that even though the pain was very slowly easing off, I could feel a small lump in the area of the pain. As of today now, (10-17-12), it's been a full three weeks since I did this and I now see a slight darkening in the area and It is slightly raised up and increasing in pain to match when I originally did this.

A friend told me he thught it might be a blood blister that is now coming to the surface and I probably need to lance it to drain it and then the pain would slack off and it would heal faster. He has no medicaql background and my clinic has about a one month waiting period for an appointment.

I have not been able to find any info anywhere about something like this. I would appreciate any thoughts, comments, or personal experiences along the same line. I'm very frustrated by not being able to play and this is taking far too long to heal.. Thanks to all who might be able to help.