yeah that is definitely Septicemia, you need to get him to a vet straight away. iv just found out my bp has it, thats how i know. it looks exactly the same. the pic looks like its in early stages but it spreads fast nd can kill them if it get to the organs so id get him seen in the next week if you can. mines just been put on a 4 weeks course of injectible antibiotics (cant remember off the top of my head what theyre called, fulcrum or something like that) and the vet said 90 percent of the time theyl make a ful recovery. good luck! just make sure shes drinking and bathe her every other day in warm water to let her drink