My sister and I are both on doxycycline for our acne. My sister ...

My sister and I are both on doxycycline for our acne. My sister is not taking it anymore because she is having chest pains although she's been off the medicine for three days now. This is my second time taking this medicine. The first time I took it I had to stop because my hands got severly burned by the sun. My hands still feel weird, but it's winter and I've been very careful with sunscreen and wearing stuff to cover my skin if I'm in the sun. This medicine works wonders on acne. Out of everything I've tried my acne improved amazingly. I guess living with irritation in my hands is worth it for me, but hopefully my sister's chest pains will go away.