Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you today. I do apologize that your question was not answered before. Different experts come online at various times; I just came online, read about your wee one’s situation, and wanted to help.
How deep is the wound?
How much blood did he vomit?
Are his gums pink or white/pale? Moist or sticky?
If you press on his belly, any tensing, tenderness, discomfort, or pain?
Could he have eaten anything harmful (ie bones, plants, chemicals, rat bait, human meds, etc)?
Can you take a photo so I can see what you are seeing? To post it, you can use the paper clip button on the tool bar above the text box (last icon). Or if you cannot see that, then post it on any site (ie Flickr, Photobucket, Imgr Instagram, etc) & paste the link here for me.