As others said... do research via internet looking at real science not random people's opinions (cochrane, pubmed, semantic scholar, etc) and then have another talk with your dermatologist. My experience is that personal research is often essential - and always valuable, a lot of doctors are not good a rethinking (for example it took decades for some doctors to use antibiotics for ulcers).
As others have mentioned use UPF 50+ clothing. Besides the traditional wide brim, I would consider KAVU Chillba, or a hat that has a veil like OR SunRunner or many of the hats from Sunday Afternoons. You could consider supplementing this with something like a a uv buff (they make a few models commemorating the camino), or a balaclava made to protect you from the sun. The nice thing about these options is they don't wash / sweat off so no need for reapplication.
You could also take a hit from the lifestyle of many people near the equator. Take a siesta when the sun is at its peak. I like the iOS application
UV Index to visualize sun insensitive, and there are many others to choose from.