My son's injury has opened - he had sticthes removed today after 8 days...?

I have medical experience AND a parent. I've always said, "better safe than sorry" and it sounds like you have a good feeling on what should have been done! Everyone heals at different lengths of time based on many factors; age, overall health, other physical issues present (immune system disorders, diabetic, etc), physical activity, diet...just a few to consider. For your peace of mind go ahead and telephone your GP. In the meantime, you can use several methods to pull the skin together; a butterfly bandage, regular bandaides, and then cover that area with a gauze pad and tape. An open wound can become infected and signs of infection are redness around the wound, puffy, extremely painful to slight touch, any drainage that looks yellow in color, lethargic, poor appetite, and check your child for a fever (above your child's normal temp...not everyone is 98.5!). Push liquids; water, juice, Popsicles, gatoraide, etc. Most children heal fast, much more than adults. Hold off on taking a bath until bleeding stops more than 24 hours.