A Little Concerned...

I noticed during feeding on Thursday (I feed in a separate container) that my Anery Corn's tongue was a kind of blackish/dark red color. Previously, it has been pink. He didn't even seem to notice the mouse, though he was active, alert, and flicking his tongue constantly. He seemed fine. I had to stab holes in the mouse's head and body for him to notice it, and even then he didn't strike or throw coils like usual, but started eating it while it was on the tongs. I let it go and put the lid on the container and he ate just fine after that.

I used a credit card to get his mouth open today, and while his tongue is still that odd color, his mouth looks fine otherwise.
His hot side temp is always around 86F, and his cool side is around 70-75 (my room temp varies). He is on aspen, has a ton of hides, always has water, and weighed in at 124g right before I fed him.

He seems perfectly healthy otherwise, perky and alert, his eyes and nose are clear, can't hear any kind of wheezing or funny breathing noises, and he breathes with his mouth closed.

I am not sure if this is just a coloring thing that aneries get when they age, but I thought I would ask and provide as much info as I could just in case. If I left anything out, let me know.
I would appreciate any answers, and if I'm all worried over nothing, feel free to laugh at me (;