Hello,
Poor guy, he may be trying to slow down to brumate, what luck. He is pretty young, too!
I think that the gel should help to soften it up some. I can't think of anything else, other than trying a baking soda & water mix into a paste to gently rub on his gums. The baking soda has a slight abrasive action that could help too.
When are you expecting the gel? I am sure his gums do get a bit irritated when you try scraping it off.
That's good he ate a superworm though, but no greens, right?
When you scraped it off before, did you use your finger nail? You could try using a toothpick, carefully to see if you could get under the edge a little bit to get it loose. If you try that, be very gentle.
Let us now how he is doing.
Tracie