BLUE TONGUE SKINKS

Hi! I've had my BTS for just over half a year now, and need help determining if this is just a minor problem I can easily fix, or if it's something I should ask my Vet about instead.
My skink recently shed, and I noticed that one of his toes seems to have a split nail or weird yellow growth of sorts? I've found that it's not stuck shed, because I soaked him for a bit and tried gently rubbing it off. It's also pretty hard. I tried my best to get a picture, but couldn't get any good ones. Here's the BEST picture I could get (it's the toe closest to his body/furthest to the right) + a quick drawing of it in mspaint

He hasn't been as active as usual because it's winter, and thus hasn't been filing his nails down just by moving around his enclosure (I have several rocks and some tile in it to help with that), if that helps at all?

Probably more of a minor problem than something that needs vet intervention. That growth appears to be just keratin build up (the protein that the nails are made of). If there is improvement as he becomes more active or it doesn't appear to get any worse, I wouldn't worry about it.