Scrub your hands with soap and cold water for a few minutes, rinsing and repeating until the ink is gone. An abrasive soap may help if there is a lot of ink on your hands.
If a bit of ink ends up on some fabric, you will want to act quickly! Dab the affected area with a clean, damp paper towel until the ink stops coming off the paper towel. Let the stain air dry for a few minutes, then spray the stain with hair spray or dab it with alcohol to loosen the ink’s grip on the fabric. Dampen two paper towels and sandwich the affected area of fabric. Blot the backside of the stained fabric to transfer the stain to the paper towel. As you are pressing, be sure to keep using fresh parts of the paper towel to avoid re-applying the ink you have just removed from your shirt. Repeat this cycle a couple times until the ink is gone.