Tire is peeling just above the treads
 

Cracks started to develop on the tire wall a month after i got the 2 new tires installed. i took it back to the store for inspection but they said, "it can happen but no worries". Today (10 months later) i'm worried. Where the wall and the treads meet, it's peeling back. After checking when these tires were manufactured, (5110), which means they were full 2.5 years old when i purchased them. I've had these tires since 5/23/2013 and has about 25,000 miles on them. Slight inner wear, mostly highway driving, no alignment issues.
Peeling on the inner is worse than the outer wall.

Should I be worried or ok to use them?