Is carotid stenosis reversable?

Not really : We don't have therapies to "melt plaque", but there are treatments to stabilize atherosclerotic plaque. These include Aspirin and aca inhibitors which can be very effective in treating non symptomatic carotid stenosis. The exception to this rule is if you have a severe stenosis greater than 60 percent the current data supports treatment (endarterectomy v. Stent).