@smg22 I have read and heard that Forteo is ineffective after Prolia. McCormick's book "Great Bones" andDr. Ben Leder's videos on You Tube (including Sequencing and Combination Approaches to Osteoporosis" make this very clear. One person on this forum posted a study on Evenity after Prolia that showed it was effective in combating rebound though effectiveness was somewhat reduced (not as much as with Forteo!). Maybe the person who posted that can post it again.

It is true that both Prolia and bisphosphonates are anti-resorptive with similar risks. For that matter, the last months of Evenity are too. But bisphosphonates are most often used to combat rebound.

Prolia puts people in a bind unfortunately. I would get a second opinion if an MD suggests Forteo after Prolia or at least show your doctor the book or videos (I know that's awkward) or have a discussion.

Forteo's bone building effect will be reduced by the prior use of Prolia. You will still build new bone and have some fracture protection with Forteo, but it can't stop the bone loss. I would start Forteo as soon as you can. It is one of the medications prescribed for osteonecrosis.
I would also want a bisphosphonate to counteract the rebound prolia bone loss. Concomittant dosages are not usually prescribed. But there is some evidence that a better balance might be obtained in special circumstances. https://link.springer.com/article/10.1007/s12020-013-9954-6
You are in the dreaded Prolia trap. But careful monitoring with bone markers can keep you safter. After the immediate rise in CTX falls, you would discontinue alendronate of risidronate. Your doctor might agree.
Prolia and the bisphosphonates create bone that is avascular. That lack of blood supply can cause necrosis of the bone. Your jaw pain may be an indication of necrotic processes in the jaw bone. The issue of rebound is separate. Prolia stops the cells that break bone down from the very last stage of development. Those cells collect over the years and when you quit Prolia they complete their development is such great numbers that they can cause multiple fractures some within the first month. That vulnerability is said to last three years without medical intervention. Forteo ( or Tymlos) will not interrupt the protection of a bisphosphonate. The bisphosphonate will slow down the accretion of new bone by Forteo.
You need the advantage of both