Infected skin tag?

Hi vets, 13 year old male staffy mix. He has had a spot on his side for a few years now with no issues and his vet said it just happens with older dogs, kind of like a skin tag, this was just a few months ago. However, today I notice that it’s drooping a lot more, red and really big with what seems to be smaller growths on it. Is this something he needs to go back to the vet for? Would he be in pain from this? The first two pics are from before and last pic is from today. Thank you for your time!

Hello - yes, as this has continued to change, it is worth taking this lovely boy back to the vets.  Two main reasons; the first is that unless it has been tested, it is impossible to be sure that a lump is benign - and even then, absolute certainty may be impossible.  The acceleration in growth may be a concern.  Secondly, whether benign or not, it may drag on the floor and become sore or infected.   You also asked - Does it hurt?  Interestingly, skin cancers are often painless at first where as inflammatory lumps eg infections / ulcers / abscesses can be quite sore.   However, once again there are no absolutes (eg cancerous lumps can scrape on the ground or ulcerate and become sore) so it is best to let your vet decide what to recvommend in each case on its own merit.  Best of luck. If you search for words like 'lump' in the blog, you will find multiple very interesting articles.