Rash on Baby Cheek for almost 4 months?!

8 month old bub had this rash on lower cheek near his mouth since October last year. It’s severity varies - light pink some days, dark red and bumpy on other days. I’ve tried the following with little or no success.

- Vaseline

- Coconut oil, jojoba oil

- Aveeno Baby Eczema Cream

- Q.V. baby lotion

- Sudocrem

- Hydrocortisone steroid cream (prescribed)

- Saline rinses

- Betadine antiseptic ointment (for when he scratches it)

Is there anyone out there who can tell me of the cause if known and remedies that have helped?? Is it normal to have had this for months?? My doctor seems to think so but it’s just not getting better at all! 😐