I completely understand looking at things from a quality of life perspective. I had a very strong response to the Erbitux- most everyone has some sort of rash but it varies in degree. What I found was that the rash got especially bad and painful for 2-3 days after the infusion and then it would improve some before it was time for the next infusion. It did get worse with each week- I skipped my last dose because I thought my chin was going to explode and fall off and it got better very quickly after stopping. So...talk with your docs, but perhaps he can start and see how he responds - if it gets to the point that quality of life is impacted then perhaps he can stop it before the full course is done. He may just get a rash and sail through the full course without too much trouble.
Good luck!