Is this too serious of a punishment?

My parents are ers. They are devout christians who firmly believe in spare the rod spoil the child. My parents do not spare the rod literally or figuratively. I got a 65 on my last report card. My dad grounded me for three weeks. (until I got my new progress report.) I got my new one and am making a 67. Needless to say I got grounded again, but I also got a . It wasn't a beating, and I'm not saying it's abuse, but I'm still sore and have welts three days later. Was this too far?