It is good to hear that Festivus is starting to do more of what was his regular practice prior to his accident.
It is, also, good that you have been able to see his tongue.
However, without a tongue, snakes can still eat. Only problem, without a tongue, is that they can't smell, for aroma particles, in the air but ... they can smell through their nose. So, could smell a prey item that is close.
Plus, the mechanics, of eating, do not require the tongue.
As for his not eating regardless, hopefully it is not that he has been put off eating mice, due to his experience, but ... other reasons, for not eating, could be that he still has a wee bit o' pain ... &/or I know that, any time after I have had surgery, my appetite went waaaaay down for awhile (so it could be that Festivus is experiencing that same thing). Course, his impending shed could have something to do with his lack of appetite (at this time) too.
Just give him time. Snakes can go a long time without food and, as long as his body condition remains pretty good, he is not in any immediate danger of starvation, etc.
I would keep with the recommended time, for his antibiotics, too.
Meanwhile ... My best thoughts, & wishes, remain with you & Festivus.