Is my western hognose sick?

Hi everyone,
I purchased a baby western hognose back in June, and he arrived healthy. Since then he’s been the perfect little snake. He eats regularly and is pretty active in his enclosure. I feed him a pinky mouse once every 6-7 days with normally no problems (i say normally no problems because he will refuse to eat one day and then will easily eat the next). I’ve read that they should eat every 5-7 days, but 5 days in between feedings seems too soon for him because he will refuse to eat until 6-7 days pass. Anyway, over the past few days I’ve noticed it seems as though he has lost a little weight and I just want to know if it’s because I’m not feeding him as often as I should or if he may be sick. Up until a few days ago he has had a nice rounded body, but now he has two little ridges that stand up on his back. They are only near his “neck” and don’t go all the way down, and I am wondering if this is due to weight loss or dehydration. Since he is eating regularly and on his own schedule I am wondering if he might be sick. I will be taking him to a vet soon but want to hear other opinions. I can’t get to a vet until this hurricane passes .