My daughter told me she picked her ear and now it's hurting. should i be concerned, or will it go away on its own without antibiotics? she's 18.

I'm sure you know: and have told her "Don't put anything bigger than your elbow in your ear." This is actually a little extreme and exaggerated, but the idea is valid. She probably has traumatized the canal, hopefully not the ear drum. If it is still hurting after 48 hours she should be examined to assess the extent of trauma. Unlikely that antibiotics will be needed. Good wishes:)