If I have an open sore near my gentiles should I wait until its healed? The summer heat is getting to me and I got a pimple by the hairline down there.

until all is checked out and healed

Yes, pimples happen & it can be hard to see down there.  Ladies learn early a knack of using a small mirror.  However, if in any doubt, you should refrain from hobbying, get it checked out.  
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Visit a dermatologist. I had a similar problem and had it cleared up within days after visiting my doctor.