The fixes may all involve sun/UV exposure avoidance or proper sun protection.
I can think of 3 possible causes.  Perhaps there's others.
Sunburn; if it's sunburn, what other fix do you need?
That reminds me: There's still UV light even on overcast days. You can get
exposed from refelctions of light off water or windows.

cutaneous lupus (which if I recall correctly may be a feature of SLE) ,
http://www.ghg.net/schwerpt/ASLFAQ/symptoms.htm#discoid (coin-shaped, hair
loss, biopsy)

cuteaneous form of porphyria - http://www.icomm.ca/geneinfo/porphyria.htm

Headlice? http://medent.usyd.edu.au/fact/headlice.html but I guess if there's
no itch, you're not scratching to cause lesions.

If it's not sunburn, can you have a dermatologist have a look and maybe biopsy
?

From the same webpage (above)
Discoid lupus can appear similar to other skin lesions. For example, rosacea,
fungal infections, sarcoidosis, seborrhea, dermatomyositis, and a sun-sensitive
rash called polymorphous light eruption can be ruled out by a simple skin
biopsy and blood tests before diagnosing DLE.

Watch for other possibles from other regulars here.
J

PS In the Lupus FAQ, there's links to good sunblock advice and links to
clothing for sunprotection. (ie headwear or a sun protective umbrella, which
would you prefer?)