I wash my hands for 5-20 minutes per hand wash 10x a day. my hands feel numb after. why is this? also is the amount of chemicals im being exposed to dangerous?

Obsessive washing?: This is serious over-washing. It probably isn't chemical, just physical irritation from so much rubbing or drying effects of soap and water. If you're protecting yourself against coronoavirus, 10x daily is probably OK, but should be only 20-30 seconds each time. If you're really doing it 5-20 min each time, it may be abnormal compulsive behavior that needs professional counseling. Good luck.