What your doctor told you has nothing to do with LASIK surgery. He warned you because you're highly myopic. High myopia seriously increases the risk of retinal tears / detachments thats why he told you to avoid traumas which may cause damage to retina.
Correction surgeries such as LASIK doesnt change it.
If I'am wrong please correct me.
But i dont think you should avoid skiing. Hitting ground or your face is even unavoidable in normal conditions. So theres no point in living with big restrictions. Just try to be more careful.
If you are still seeing your Lasik DR, find another one!
Not sure what country you are from but I had Lasik done 12 years ago and ski regularily, run every second day, lift weights, play football(American style) and fall off an occassional chair.
Get on with your life and have a great day.