Whats wrong with my Russian tortoise

I 've had him for six years and he's always been healthy.He stays outside all year round(he hibernates from October to April)He has a large (6x10 ft.)enclosure with all kinds of plants for him to nibble on and a house,water pan,etc.He's fed all kinds of greens,flowers,weeds. Also carrots,green beans,apples,and occasionally bananas and berries.He also likes an earthworm now and then.But lately he acts as if he can't open his mouth all the way;he wants to eat,but he acts as though it's painful to open his mouth. I took him to the vet,and he was given Baytril,but he still won't ,or can't eat,so I' ve been pureeing his food and force-feeding him with a syringe(no easy feat,let me tell you).I noticed that his tongue looks red.Could it be a vitamin deficiency,or stomatitis?My vet is good,but she is not a reptile specialist,and I don't have the 300 bucks to take him to the Reptile vet right now.Can anyone help?

Vitamin deficency? Possible- the diet you describe is pretty good, but you don't mention vitamin suppliments or calcium suppliments.

Stomatitis? Always a risk, but there is usually white exudate involved- although this might be an early stage.

Other options- I wonder about jaw injury. I am also concerned about the force feeding. Statistically, force feeding is less healthy than letting the animal go hungry- especially a tortoise that can go a month or two safely without food if water is offered.

The Baytril is an anti-biotic that should help against many conditions, but won't help with some of the options.