Sorry I can't help you with the heart palpitations, I'm not sure what could be going on there. The only advice I would give for this is to listen to your body and pay attention. If you think you should stop, then do so! I used to have heart palpitations before I started cleansing, but they have gone away.
As for the rash, this can happen. Your body is detoxing something through your skin. If you want to help it along, you could try something like a clay pack.