Rabbit with bald spot?

I got back from vacation today and picked up my rabbit from my neighbors house and when i got home i noticed that she had a little bald spot on the bottom (the part that attaches to head) of the ear. It is red and she inches it infrequently like when she is grooming her self, could thats have been caused buy stress from not being at home? or what? shes eating,drinking and pooping all the same