Most vets are used to seeing things like ball pythons and boas, most are not used to things like retics or how to handle them properly. The fact you had to go back and forth to the vet for something as simple as a broken tooth is proof of that... Retics commonly have these problems. You're going to be spending a fortune on things that will do little good..
In the event of a tooth lodged in the gum, it NEEDS to be massaged out with tweezers, if you are uncomfortable getting used to working on your snake to help it get better- I HIGHLY recommend rehoming it and finding another snake, as these are fairly common problems you should be able to rectify with relative ease. In the case of infections- most vets will give you a typical antibiotic regiment, and to be honest- it won't do much for your snake's mouth issues. If it is an open wound in the mouth, create a chlorahexadine solution that you can spray into the mouth via a spray bottle. Apply polysporin (not the pain killing kind, the clear kind) to any open wounds, and it will heal right up with relative ease.
Again, a picture would help a great deal- if it's pushing, the vet won't be able to do anything other than charge you a bunch of money for some useless stuff that won't help your snake, and in fact may stress it out even more.
If you need any help with your retic or fixing it up, you're always welcome to PM me. I've spent hours inside mine's mouth cleaning out a pretty gnarly infection from when I got him, working his gum s free of broken teeth, and even fixing up some poorly managed scar tissue I found. He's looking 100% better and is back in breed mode with my ladies
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Dark- I just realized you're location says Denver. I'm located in Colorado Springs. While I work all this week 9 hour shifts - I do have sunday/monday off as well as the entire week from the 12-18th off. I'd be more than happy to take a look in person for you and help you out with him if you'd like to make the drive down this way. It'd probably be a lot cheaper than a vet, and I can show you how to treat it yourself in the future.