I only started running after my piercing had been in place for a few months and was well healed so I'm not sure what it would be like with a 6 day gap. Perhaps the person doing the piercing could give you some advice about how to adapt the after care. They could advise as to whether it is better to leave it open to the air or if it is better to cover it with gauze / micropore tape.
Personally, I'd wait til after the races were done but have no expert knowledge to back that up.
I only run half marathons. Don't run anything longer distance than that but I found that gels gave me a very upset stomach. Won't go into detail.
Got some advice from a thread on here a while back.That was, to try dextrose tablets. I buy "Dextro Energy". A pack of 14 tablets cost about 60p from most supermarkets. I have two tablets about 10/15 minutes before a race or long run and another 2 an hour into the run. They seem to help me with energy levels. I also used to get quite nauseous after long runs too and that's stopped.