Had yeast infection in butt crack but has cleared. Now I have a small white bump, that is sometimes a little painful where my cheeks meet. Related?

Cannot say. dermatologic conditions are hard to discuss without seeing them. and can be a white head/infection/boil or scar or a totally different growth (skin tag, etc.)
Bacterial infection. You could have developed a secondary bacterial infection / abscess / boil / furuncle in an area that was inflamed / raw due to the yeast infection. It's hard to know without examination. Consider using HealthTap Prime or talking to ur doctor about ur symptoms. Are you having fever? chills? sweats? drainage from the site? These are signs of infection. All the best, thanks for using HealthTap.