Kris too used the "fingers". This worked very well. He forced the fingers in up to 5 times per hour. Gradually worked up to 3 fingers. He did this intensively for about 6 weeks and can now open his mouth pretty well.
Our surgeon and SLT preferred this method to the Therabite.
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!