Teething for over a month but still nothing

My daughter is almost 8mo and got her bottom two teeth when she was just shy of 6mo. For the last month, she has been having all the signs of teething again (rashy cheeks, fussy, not sleeping well, chewing on everything, drooling like crazy, and swollen gums). She even has had slits in her top gums for the last two weeks but there's still no sign of her teeth actually cutting through. Has anyone else had this happen? How long did your little one's top two teeth take to cut through?