Scarred ventral scales?

Hi, I was cleaning out my ball python enclosure today and noticed something that I have never seen. I took my male ball python out and noticed that he had what appeared to be scars along a significant portion his ventral scales. I have no clue what this could be, I've had my ball pythons in the same setup for years the only thing I've somewhat recently changed is I replaced my old substrate paper towels & newspaper with reptile bark with a bit of moss. I am not sure whether it could be that, if maybe the other ball python in the enclosure pushed up against a hide rose it a bit and dropped it on his belly somehow or if it could be due to him rubbing against a somewhat rough edge on something in the enclosure. Another thing that came into my mind was maybe scale rot or burns, I am not really sure what causes scale rot but I haven't changed the heat in the enclosure so I don't think it's a burn. Has anybody ever seen anything like this before? Could it something major like scale rot? Will they heal if they are just scars after a shed?

Please don't flame me for having my ball pythons together, they've been together for 8 years without any issues and I have plans to separate them really soon anyway, I just have to move a desk out of my room to make space for the new equipment which I already have ready.

Any advice or opinions would be greatly appreciated.
http://i44.photobucket.com/albums/f1...ps9436bb49.jpghttp://i44.photobucket.com/albums/f1...ps6ba7914d.jpghttp://i44.photobucket.com/albums/f1...ps52219ee3.jpg

Scale rot tends to be brought on by wet substrate over a long period of time.

There is quite a lot of scale damage there so it does look like something is going wrong. -Is there any sign he is coming up to a shed?

His belly does appear to be slightly pink but aside from that there are no obvious signs he's going into shed. I feel like I should clarify that the female ball python I have been keeping with him has no signs of anything wrong with her belly before I mention this, but I did add some water to the substrate before I put it into their tank the last time I cleaned it to hopefully raise humidity so maybe it is scale rot :( The damage does seem significant and I have no idea how I didn't realize it until now nor do I know how long it's been like that. Do you believe a vet visit will be necessary? Is there a fix for scale rot?

Are you keeping 2 bps in the same enclosure ?

Yes, they've been together for 8 years with no problems yet. I planed on separating them earlier in the year and actually attempting to breed them but it took far longer than expected to get the thermostat I ordered in so I was unable to do so. I am currently dealing with exams so I won't be able to separate them for a little bit unless absolutely necessary.