A really hard bump to the lower back of the head can sometimes be a problem...probably no big deal though and I wouldn't lose sleep over it unless 1. that's where she hit it and 2. she becomes nauseated and/or more lethargic than usual at this time of night. Just keep an eye on her, give her some tylenol or ibuprofen like ReneeK3 says, and try to relax! She's really probably fine. I sure don't want to scare you (because honestly its most likely unnecessary) but you should know what to look out for just in case. And trust your instinct! If something doesn't feel quite right, then call your ped.
Hope this helps -
at 12:14 AM on Feb. 3, 2009