My dog had maggots and worming then was taken to the vet and cured,he puked blood like color What is it?

i took him to the vet and the vet gave medicines for his maggots in his wound and he had worming both were kinda cured and he looks fine but vomitted purple color or blood color and it had solid stuff like a blood clot or Maggots what is it is it the effect of worming medicines or is this maggots of his wound OR is it Blood PLZZZZZ HELP AND READ IT !! MY DOG NEEDS HELP!