Your puppy has gotten into something and cut himself. This can be frustrating and potentially even scary for both you and your pup. The first thing you will need to do is check for multiple cuts, find them all, isolate them, and get them clean. To know what your puppy cut himself on is helpful so you can remove it from his space. If you need to remove material such as glass from your puppy’s cut, a saline solution can help rinse out dirt and debris.
Washing the cut with a mild soap or dog shampoo after a good rinsing will help to eliminate bacteria.
Your puppy's skin will be very tender to the touch. He may wince and cry or may potentially even not sit still long enough for you to get him clean. Be gentle and use a calm relaxed tone when you speak to him. This will help keep him calm.