Do reptiles have a different way of reacting to the sun though? I'm going to struggle to explain but as they use heat from the sun to raise their body temperature is it moved away from the skin rapidly? I'm assuming that they have a stronger "sun metabolism" than mammals.
From what I understand, it isn't a problem of sun energy dissipation, Uv particles of light have high energy, and when they zoom through space and smack into skin cells they smash parts of the DNA in the skin cells, and DNA is needed to creat chemistry the body needs for life... DNA is a streamer and uv is the scissors!!
In short UV rips cellular dna/rna up, we (humans) go red after sunburn due to extra blood flow needed to repair our cells or to fix areas of dead cells though uv exposure.
If heat transfer was the problem we wouldn't get burned underwater as the water would dissipate our skin heat, but what causes sunburn isn't heat but smashed skin cells from high energy UV particles.
I assume without this melanin, then there is no UV protection for a snake, and I would assume ( I don't know for a fact) that their skin cells may be at risk of this UV smashing DNA in full sun, however snake skin is reptilian and may hold out better than mammal skin, I don't know of their skin makeup protects better than humans without melanin, but unless I could confirm this, I wouldn't be too flippant about a lot of sun.
I also assume they need the sun for vitamin D? So I guess they may need a bit of sun, perhaps get it a sun smart t shirt.....