I agree with the member who suggested that you track the car in the future. That is, if you don't get into any further trouble with your license/registration etc. Exceeding the limit by 41mph is dangerous for you and for others. Presumably, the 50mph road is not designed for 90mph speeds, so I'll assume that you are incredibly lucky to have not hurt yourself or others.
Hopefully you will get to keep your license. Also, hopefully, you will get nailed with max points on your license, and see an appreciable rise in your insurance rate. Unfortunately, those are the only factors that dissuade speeders from succumbing to the temptation.