Strange a vet would only advise one shot of baytril. They typically do 3-4 rounds for infections. Is the wound site improving or is it still red and swollen? A small amount of blood should not be a concern after shedding so long as there is not sign of prolapse. If the snake is slightly dehydrated or there is constipation, straining can cause this as well as rough shed.
I would be more concerned about the splinter site and making sure it is not showing worse signs. Also keep a look for the cloaca and vent area to make sure it does not get swollen or otherwise inflamed