White's with leprosy

[beyowulf]

OK, I know it isn't actually leprosy, but my White's has some sort of boils or something on his leg and underside. There are only two sores with fluid inside.

I figure it's because I was mixing the dechlorinator in the wrong proportions (adding too much), but someone suggested his problems are due to mineral deficiency.

I fixed the water problem, and dusted his crickets. I was just wondering if anyone else had experienced this problem and had any advice to give.