just returned from a miserable week in the virgin islands. am taking 200 mg doxy twice/day. had spf 45 on as well as floppy hat, long sleeves and pants.....i lasted two days with limited exposure to the sun. my hands and lower half of my face were (are) so sunburned that my slkin felt like it was on fire. exposure to water (i.e. washing hands) felt like ice. i suspect that the sunburn on my hands resulted from only 30 minutes of driving (hands on wheel). bottom line is that even spf 45 won't protect you from the "reaction". i say that because my hands are now back to normal (7 days later) but didn't peel or blister like a normal sunburn. leads me to believe its more a reaction to the sun's radiation. face is still nightmarishly red. lips bleeding and raw......