Colposcopy: to nitrous or not to nitrous

Having a colposcopy done on Friday, I initially was told to take two Tylenol 2 hours before hand to minimize discomfort. I was then also offered to add nitrous oxide to the procedure. It is $100 out of pocket up front which seems like a lot if it’s not necessary and I am out of FSA funds for this year. Just wondering about others’ experiences and whether or not I should add it and fork over the $.