Black crusty scabs in my shih tzu's right inner ear?

I was lookin in her ears tonight and noticed in one there were three seperate black marks which i thought was maybe ear wax , so i tried to clean it carefully and soon realised whatever it was , was crusty :( now im wondering if she has an ear infection, its only in one ear and i havent noticed it before tonight. We have had some pretty hot weather lately could this be causing it? I bath her every week and take her to the groomers every 6 weeks. Any advice would be appreciated , she is my bby and the least thing wrong worries me :( thanx in advance :)