That's exactly what that is. It is Covering that was over heated. But it's an easy fix.

Just lay a strip of covering over it Like in the first pic below (I made the patch red just so it would stand out - Note the cut corners). You may remove the damaged section first if you choose to (You may want to if it's wrinkled)

I also notice that the stripe is bowed out slightly (You can see the blue peaking out from under my red patch in the middle). If that really bugs you, you can lay a strip of white down first as in the second pic