Hello CharlaB, welcome to the forum. The ear canal attachment is much deeper than you thought, more along the side of the skull above the mandible attachment. As long as you didn't cut the outer ear skin, you should be OK but without seeing it there's no way to tell for sure. You should practice skinning more mammals to be confident in doing it properly. It comes with experience like anything. The inner ear skin will be adhered to your earliner so you can blend the junction between the two with Apoxie Sculpt anyway. I would leave the cartilage in the ear and use an earliner that's made for placement between the cartilage and the skin on the back of the ear. One type that comes to mind is the earliner sold by Brian Harness of Ozark Woods. Call him at 800-467-0369 for his product catalog. If I were you, I'd get his video on mounting a raccoon if you don't already have it:
https://www.taxidermytrainingunlimited.com/BH-Raccoon.html . It doesn't include the skinning process but you'll gain a better understanding of how the ear mounting process works. Let us know how you do.