Teething

Holland is teething.  After all of the false alarms I'm pretty sure this time it is true.  She has the little bump in her mouth and I am pretty sure I can see two little teeth surfacing.  She is pretty fussy and wont let me get a good look but she sure seems to calm down when I put the orasol gel on her little gums.  Poor kiddo.  How long is this supposed to last?