This is from my holistic vet and THIS WORKS. Take your thumb and forefinger and just "pluck" at the lump. Not hard and don't be painful ... but literally just pick up the whole lump and let it snap back.
The point is to stimulate blood flow in the area -- this will help any fluids dissipate and gets the tissue to heal.
If you can get to a health store, get a homeopathic called "Thuja". don't get the 'strong' one (if it's Boiron, get the dark blue tube, not the light blue but if the light is all they have that's ok).
Give 4-5 pellets twice a day for 3-4 days (if you get the light blue container only use 1-2 pellets at a time & they ARE tiny).
Don't touch the pellets with your fingers. Skin oil destroys them -- they are complicated little dispensers -- you gotta twist the top with it upside down and let it drop onto a piece of paper. Fold the paper and crush the pellet balls -- and then pour it into his mouth onto his tongue.
Do *not* put these in food. The stuff needs to dissolve on his tongue. They are sweet and he'll think it's a treat if you approach it that way. The thuja will help detox his body from the shots.
Then go back to desensitizing him at the vets. Don't play fair -- take the one thing he thinks is BEST in the whole world and take it with you for a treat. Peanut butter crackers? Bits of steak? Make this count.
Big deal -- DO NOT be *afraid*. If you get all wigged out and worried so will the dog. That is a bigger deal than you might think -- they SO ping off our fears it's not funny. If you are all worried about a vet visit and how he'll do HE will worry.
The other day, my dog Billy had to get blood drawn again. Now I've gone to great lengths to make sure he isn't scared at the vet (he was ... like your dog!!). And after this last blood draw, which was kinda tough, I made sure this last week that I took absolutely knock-em-out SUPERB treats to help him make 'nice' with the vet after she had to take more blood.
What'd I take? WATERMELON!!!
It was messy. Oh yeah. Was it convenient? Nope. BUT, I know my dog and I know what he loves more than anything -- the vet got a kick out of giving him this "ultimate treat" (and he was ape nuts for it).
But beyond that? She *appreciated* the fact that I was taking the time to make sure he wasn't afraid of her. We knew he loved her and she's great with him -- but I wasn't getting that started again.
Watermelon probably isn't gonna work for you -- I didn't mean that. I DID mean to think out of the box -- out of the treat box to be specific. Use what will work!!!
Drop treats off at the vet before hand -- and call them before hand and arrange what time you will be there with him. Let a tech come out to your car!! Don't even stress it by him going in.
You might want to stack the deck more in your favor -- give him a little valerian tincture before you get there (it takes about 5 minutes to work and you can mix it with a bit of peanut butter). That will help the dog relax and if you repeat that a few times you'll find it will make things easier.
Take care Jen - this is NOT a big deal. Yes, it may be from the shot but working thru it like this is pretty easy and it will go away if you do what I said above.
You're thinking about "injection site sarcoma" and such -- and it doesn't ever develop that quickly. I rarely ever tell folks it's "not much" -- but in this case I can tell you it's not a big deal. You have found it early and by stimulating the area you will get it to go down.
You're a good dog mom and you'll learn to be better. But keep on trying to desensitize him to the vets -- let this current scare only make you more stubborn to make sure he CAN go to the vet and not get freaked. It takes TIME and I truly commend you in a big way for being so proactive!!! Good for you!!