Nelie, I have no info or experience with this, but I wondered if the dentist could somehow realign the teeth that have "migrated" by using rubber bands or braces, in the hopes that your current "flap" would then fit again.
The other thing I have to offer is my best wishes that your therabyte exercises will work well enough so that by January you will be able to open your jaw enough for the impressions to be taken for a new flap.
Hang in there!!

Andrea