A hand job is considered a 'safer' sexual encounter. you gave the hand job though. This is far less risk. Would you get chlamydia through sores on your hands when giving a hand job? You would not get chlamydia of the hand.
Hand jobs do not transmit STDs - hands never transmit them.
STDs also don't go through clothing, no matter how thin.
If your hands are cracked, you should reconsider hand jobs, though. If someone has a fungal or other bacterial infection (staph, MRSA, etc.), you could easily get that on your hands.