I was recently prescribed Doxycycline Hyclate for periodical derm...

I was recently prescribed Doxycycline Hyclate for periodical dermatitis (contact dermatitis around the mouth) It started to get rid of this red, ugly rash right away, however, 2 weeks into the medicine, my head is killing me! I have HORRIBLE non-stop head aches. My head and face hurt like I have one monstrous head ache, and, aspirin does not help! I have also been so angry (hard not to be when your head is pounding!) I also had terrific nausea. Could not sleep at night, and, I had some weird nightmares! I stopped taking it and will be calling my Doctor today to tell him to give me something else.