What Causes Reoccurring Blisters On Lips?

I have a blister on the bottom of my lip in the centre of the lip. it keeps reoccuring every week. my lips swell up and then get very dry and start to peal. I also notice a little white blister on the inside of my upper lip. this problem has become very painful. I stopped taking my vitiams, calcuim, vitD, omega 3-6-9, I also have to take Diovan 80mg for blood pressure. around late december early january of this year my doctor put me on Actenal for the starting of osteoparosis and it seem the the problem with my lips started a few weeks after that. do I stopped taking that as well. My doctor as well as a walk-in-clinic doctor told that they didn't know what could be causing this. I've used abreva on it but it burns like hell. I'm sure if it works for this type of thing. I don't know what to do to treat the problem