Hi don't know if you've heard of it or not but you could always try calling Health Direct in your area. Free 24/7 service where you get through to registered nurses who take you through symptoms etc and then advise what you can do and if you need to get bub checked out by doctor or not. As diahorea has been continuing for several days now they now suggest going back to docs or again may say no need as long as she is still taking in plenty of fluids - bit difficult to tell about wet nappies if she has diahorea !!!! Personally I have found them great when I've been unsure as to whether I need to go to docs or not. Number (which works country wide as far as I know) is 1800 022 222). Even if you don't use for this is good number to have handy for other things in the future.

Can't comment on teething causing diahorrea as it hasn't happened with us can get definitely attest to red raw little bums :-(. Think bananas are supposed to be good for blocking them up so you could try that and see if it helps.