Thick tailed gecko skin issue

[Heliamphora]

Hello all, I have recently notice the development of what looks to be like an abrasion around the right nostril of one of my juvenile thick tailed geckos. Other than licking at the lesion, the animal seems to show no other signs of distress and is eating three medium crickets, dusted every second feed with calcium supplement, every night. It is currently in a three litre sistema tub with no additional heating, fine sand and sifted peat for media, half toilet rolls as hides on the dry side, with the most side having the sides of the tub misted every second day. Bellow is a picture of the affected nostril.

I am after any information on the best way to treat such an injury ( antiseptics, husbandry modification, etc..)
Any help is greatly appreciated,
thanks, Pat.

 

[caliherp]

Did it recently have a shed? It may be due to rubbing up aginst something to ruff.

 

[Heliamphora]

It shed about two weeks ago. Apart from a small bottle cap used as a water dish, and the cardboard hide, there is nothing else used to furnish the enclosures.