I Was Treated For Colitis. I Started Taking Mesa Salem

I was treated for colitis. I started taking Mesa Salem mean maybe 2 weeks ago and I started having severe throbbing headaches I have arm and leg rashes just with a little bumps that just appeared and a throbbing headache for which I noticed it shows up when I stand up or sit down or with movement and I'm not understanding what's going on can you help me understand please?