What Are The Signs And Symptoms Of Ear Damage?

Good morning. I'm wondering if you can "scald" your middle ear or eardrum? I'm at the end of a cold and my ear has had pressure. My doctor said it was fine to put oil in, but not too much. I've done this many time in the past and put in a little ear oil in the right ear (I checked and the oil felt warm to the touch) but I over did the heat and it was TOO hot when put it in my ear and burned! I just want to know iwhat signs I should look if I've done some real damage, or if it's OK to let it go for a few days?