Diesel, wtf. I'm no doctor and I would have taken you to the hospital if I saw that.
Keep going to doctors until that thing heals up. You need a doctor who has been to Iraq or Afghanistan.
Find a specialist.
I got burned once. They took me to the local hospital. They knew nothing about burns. Got home 4 days later, next doctor knew nothing about burns. Next day new doctor says you need to be in a burn unit. Burn unit got me straight.
That is not the type of wound that you come back in a few months to see how your are doing.
Contact Dr. Mark http://www.sandersclinic.net/mrksnders.html
He is on KTMtalk.com under > Injuries - Riders down but not out. You may have to join (no cost) to access the threads.
I hope you heal quickly.