I think i have shingles on my upper buttocks, where my crack starts. theres a red swollen area with blisters and its painful?

Shingles? Herpes?: This could be herpes zoster (shingles), but sexually acquired herpes simplex virus (HSV) also is possible. Recurrent genital herpes oubreaks can occur nearby non-genital areas like buttocks, upper thighs, pubic area, etc. See a doctor ASAP for PCR testing to determine the exact cause. If your doctor agrees either HSV or zoster is likely, you need immediate Rx (e.g. valacyclovir) to speed healing.