Glad they are munching hay. And you just try not to worry so much ...
You see once an area is sensitised on a rabbit, they go back and chew on it whether there's anything wrong or not. The prime cause can have long since disappeared, but they just carry on, as you know.
One more thing (bet you're sick of my constant suggestions [emoji38]) is trying Gabapentin for nerve damage pain:
Maria Kubiak says (I know I've quoted before - bear with me)
I use tramadol quite frequently in rabbits, guinea pigs and chinchillas with pain that is not controlled by non-steroidals like metacam, or where NSAIDs can't be used due to other health issues. It works well to control soft tissue pain, less well for bony pain and rarely causes sedation and I've had no adverse reactions. Doses required for pain relief in bunnies are much higher than in cats and dogs.
Gabapentin I use only for nerve-damage related pain so far less frequently but has seemed to give some relief in a number of these cases.
Now it's not without it's side effects, and your vet may be reluctant ....
https://www.researchgate.net/public...itis_leads_to_serious_side-effects_in_rabbits
It's a good article to print off and show the vet as to the uses and side effects of Gabapentin.
In addition I would get the area shaved (constantly) and apply a non steroidal healing cream.