It is not unusual for swelling to take place temporarily. Make sure your Doctor is aware of your concern next time you go in. There are several treatments left I am assuming. The fourth week is when mine began noticeable shrinking.

Age 55 HPV 16+ SCC, BOT 050613 Stage IV
great team at OSU
Tx 6 weeks of rad started June 3
8 weeks of chemo started May 28
RTOG Phase III trial Cetuximab group.
Treatment completed 7/16/2013
PET Scan completed 10/08/13
Results discussed 10/11/13
NED - Free but am I
Next part of the journey?
1year PET 10/24/14 NED
Good reports now 10 years out.