Benzoyl Peroxide and Sunburn

I was just wondering..

I know benzoyl peroxide increases skin's sensitivity to sun, but i only use it as a spot treatment.  So i always assumed it only increases sensitivity in the area it's applied, and never worried about it much.  i don't use the stuff much but i put it in a handful of spots before bed last night.

today i went tanning and my whole face burned, pretty bad... (which is unusualy since i go tanning every day, but i also stopped using my SPF 15 face lotion prior to tanning because my face was way paler than the rest of my body...but today wasn't the first day)

does anybody know if benzo only increases sensitivity where it's applied or if it would've affected my entire face

[LilHypochondriac]

oh and i should add, i washed off the benzoyl peroxide before tanning