I have an epiphone guitar that is acoustic/electric. Basically you can hook it up to an amp and it has a built in tuner. To use that ability, it requires batteries. I had a preformance yesterday, and I guess I lost the cover to the battery box. It isn't too big of a deal minus the batteries can fall out and it looks as ugly as heck because there's a white sticker saying the battery type. Should I contact the company or cut my losses and not worry about it?

Sure, contact Epi with your model and serial # and a pic of the missing piece. They will probably send you a new one for a $.... Or just put tape over it and live with the shame.
"Your sound is in your hands as much as anything. It's the way you pick, and the way you hold the guitar, more than it is the amp or the guitar you use." -- Stevie Ray Vaughan

"Anybody can play. The note is only 20 percent. The attitude of the motherfucker who plays it is 80 percent." -- Miles Davis

Guthrie on tone: https://www.youtube.com/watch?v=zmohdG9lLqY
Until your new cover arrives, a slab of duct-tape tells everyone you are a well-travelled and experienced player.

A couple of bullet holes in the guitar don't hurt either.....
^^^For months a piece of tape (I prefer masking) was the battery holder for the active tone controls on one of my solidbody bitsas. I only tidied at up at the request of the buyer.

An easily detachable cover isn't a good design. - I'm surprised that Shadow's Teutonic efficiency missed that. If/when the new cover comes, I would stick a piece of tape over it for good measure.