By cupping, I presume you are referring to abnormal wear on the tire tread -- the surface of the tire that contacts the road. I don't believe this could be due to rubbing up on a curb. A sidewall issue severe enough to produce cupping would more than likely result in a failed sidewall before any appreciable cupping was produced.
More than likely, you have suspension, alignment, or tire balance issues that you were unaware of that produced the cupping. You may not have noticed the tread wear until you had a reason to look closely--the reason being the encounter with the curb.
Tires are the canaries in the coal mine when it comes to alerts about suspension and alignment issues. Check your shocks, bushings, and balance. And you may just want to replace the tire rather than keep it, then worrying about how many miles you can squeeze out of it.
From reference.com -- "The most common cause of front tire cupping is worn, bent, cracked or otherwise damaged suspension components. Some front tire cupping also occurs when the given wheel is out of alignment. Another possible cause of this phenomenon is unbalanced wheels, although this is rarely the sole cause."
Good luck with troubleshooting your tire issue.