First, if it is severe enough, go see a doctor to rule out any bigger pathology. Any numbness into your fingers and lack of capillary refill could be a sign of a compartment syndrome. It's not a high likelihood for that though.
More than likely, you upped your volume or load or intensity in exercises that require more grip work. Start with some soft tissue work on your forearms, sleep with your forearms covered at night, and begin with some basic stretching and rehab based exercises for the forearm/hands/fingers. Ice cup massages will help when they are bothersome and after activity too.