Call his doctor. Could just be a minor seroma (fluid collection) that needed to drain. If there is no swelling, redness, or pus discharging, it should be OK to wait and see. Seroma drainage is clear, pink-tinged or straw color. The drainage should reduce pretty quickly. Watch his temp for a fever. If the drainage picks up instead of slowing, or he spkies a fever, you'll need to bite the bullet and be seen In urgent care or the ER. But, it should be OK until Monday.
Jan