Red spots on forearm?

dont know what this is, but everytime i wear my sleeve rolled up and its sunny, i start to develop clusters of red spots on my arms, they sometimes have a boss on them, but when its cool or they have'nt been exposed to sunlight, they dissapear. minus stating the obvious (sunlight) whats cause this? its starting to look minging, and with summer coming hopefully, i dont wanna enjoy to wear long sleeved t's.Red spots on forearm?
I get that. When im thaw out, my arms turn really red and mottled.( i call it cornedbeef arms)
I use a suitable body scrub on my arms a few times a week and moisturise. This seems to relieve the spots and texture, My arms are still quite red though, everyone think its sunburn. Ive trie fake sunburn and thats helps a bit beside the colour, but be careful not to put too much on, cos it can be paid it look worse
It makes me totally self conscious about showing my arms.
Im thinking around going to my GP for some advice.
There is one possibility ...
Exposure to some plant sap can cause skin photosensitivity. The giant hogweed is all right known for this. Can be harsh and long lived. Kids used the hogweed stems as blowtubes and developed blisters and spots on their lips within sunlight.
Visit to doc strongly recommended but think if you hold been essential strange or new plants just this minute.
You are exhibiting UV sensitivity and you must be careful not to expose yourself unnecessarily to the sun. Use a large sunblock cream if you have to be in motion into the sun, even for short periods. Your criticism start off as rash, but some of these rashes may become something more serious. Don't embezzle chances.
could be ringworm