[anji1971]

James beat me to it, but I was about to say scale rot aka "Blister disease" as well.

Blister disease: Is common in many captive reptiles. It is most often associated with the maintenance of these animals in damp, filthy environments. The first sign is usually a pink to red appearance of the bottom-most scales. Later, these scales become swollen and infected by bacteria and fungi. Treatment involves use of topical and injectable antibiotics. Further, the underlying sanitation and hygiene problems must be corrected. Blister disease is preventable if you are aware of it and if the enclosure in which captive snakes are housed is kept dry and scrupulously clean.

Please keep in mind that this doesn't mean you caused it Shanley!! He could have been hanging around somewhere damp and dirty outside, to start it off. Just be sure to keep everything dry, sanitized, and use a good antibiotic ointment, as has already been mentioned by the others.