Dude, totally possible to injure or overstrain your joints, forearms, fingers etc when doing grippers. I can hardly type this as my arm is so sore and my fingers hardly work after doing cheat closes with #3 last night...
My newbie suggestion: hand massage, therapy and pampering. Massage (or better yet, get someone else to massage
) your hands, joints, forarms, where ever the pain is. Some gurus swear on doing hot/cold baths for their hands, so you have a bucket with hot water and then another one with cold and you swap between them. Some swear on this, personally i just keep my arm in ice cold water sometimes if i've pushed it to the limits.
You'll be suprised how fast your hand gets used to all the battering. Only about 3 months ago i couldn't cheat close the #2, the pain was too much, my fingers, palm etc just couldn't take it. Now i can do #3 cheat shuts and negatives no probs, well, short of being totally immobilised for hours afterwards, lol!