You can take pics of scalp P.. or around the hairline if it shows there.. you just need a friendly pair of hands to hold the camera

and a good light, I've found a flexible desk light the best!
As its on your scalp and you have the itch, be extra carefull not to scratch.. if your scalp P is anything like mine it can get infected really easily once you break the skin so gloves on or sit on your hands!!

I'm using normal shampoo now but before i could only use soap substitute as a shampoo, i reacted to anything else, even coal tar shampoos.. prob best to ask your doc if there is any conflict, there shouldnt be but its always best to check..