Well Paul. This sounds interesting.
I do know that the ENTs/ Otolaryngologists use Collagen over here for a number of purposes , but I don't really know what they are for.
Our local hospital would not fund the Collagen for Kris so our ENT got their colleagues in Auckland to give us some by the back door method.
It has worked a treat for Kris. So, I really hope you have some success too- albeit for a different purpose.
Tammy

Caregiver/advocate to Husband Kris age 59@ diagnosis
DX Dec '10 SCC BOT T4aN2bM0 HPV+ve.Cisplatin x3 35 IMRT.
PET 6/11 clear.
R) level 2-4 neck dissection 8/1/11 to remove residual node - necrotic with NED
Feb '12 Ca back.. 3/8/12 total glossectomy/laryngectomy/bilat neck dissection/partial pharyngectomy etc. clear margins. All nodes negative for disease. PEG in.
March 2017 - 5 years disease free. Woohoo!