You can update me with videos and more pictures along with detailed history ,

Hi, Itching nd swelling near the anus in dogs can be caused by several issues such as anal gland impaction or inf., parasitic infestation (like worms or fleas), allergic reactions or localized skin inf. What you can do your own at home- Check for visible parasites (like fleas/ticks). Deworm your dog if it hasn't been done in last 1–2 m. Warm compress the area to reduce swelling. Prevent licking orbiting the area by using an e-collar. Keep the area clean nd dry nd avoid applying any human meds/creams.

Need more information better to book a consultation for the same

Better to get a physical examination done by a vet.

We need proper history and examination before prescribing the medicines