-ne

back + -ne → bacne/backne

butt + -ne → buttne

Yeast infections are different from acne (or "rackne").

2008, Marisa C. Weiss, Isabel Friedman, Taking Care of Your "Girls": A Breast Health Guide for Girls, Teens, and In-Betweens, New York, N.Y.: Three Rivers Press, →ISBN, page 63

It's so refreshing to be with a guy who actually wants to be seen with you in the daytime that you convince yourself you can ignore the busted grille, the acne, backne, and chestne, or the fact that YOU normally wouldn't want to be seen with HIM in the daytime if you weren't so tired/desperate/horny. But resist.

2012, Heather Rutman, The Girl's Guide to Depravity: How to Get Laid Without Getting Screwed, Philadelphia, P.A.; London: Running Press, →ISBN, page 79

It's fucking weird. Yes, it's just a job, but most people's jobs don't consist of slamming your vagina against the flaccid, nylon-wrapped penis of a guy wearing massive amounts of foundation to conceal his assne.

2014, Lena Dunham, Not That Kind of Girl: A Young Woman Tells You What She's "Learned", New York, N.Y.: Random House, →ISBN, page 104