It sounds like scale rot to me, but I'm no vet. If it is, it will need to be treated. You can soak daily in a weak Betadine solution (mixed with water to the color of very weak tea) for maybe ten minutes at a time. Make sure you place it back in a clean cage with either newspaper or paper towels as a substrate...wood shavings and other substrates can act as an abrasive and aggravate the problem. Scale rot in captive animals is usually caused from the snake sitting in urine or unclean cage conditions. Since it's wild caught, that could be something it picked up in the wild. If I remember correctly, it's a bacterial infection of sorts. It probably wouldn't hurt to have it looked at by a vet, but you could start the Betadine washes in the meantime.
Raven