Sores over neck and lower back

My cat garfield has recently been suffering with sores on the front of his neck, lower back and by his tail. They look red and sore, however not weeping. We have been treating them with a cat friendly aleo and witchazel cream, which has been working slowly. Weve also started to apply sudocream. Any ideas what it could be? If it continues to not clear we will be taking him to the vets. Thankyou

Photo would be helpful.

just reapplied cream will take one in about an hour or so when its absorbed

Yes, photos would help. It would be a good idea to take him to the vet's office to rule out ringworm, which is common in cats and something humans can catch from them.

Just realised i had one on here from earlier, the white is the sudocream we havve been putting on it. Thanks for getting back to me guys

I think that definitely calls for a vet visit. Did your vet okay the use of Sudocrem? Many creams for human use are toxic for cats -I don't know whether that applies to Sudocrem.

Could be from flea allergy or ringworm, since he goes out I would take him to vet.