Ok first off your a good looking guy with or without hair, you seem really down on yourself because of your scalp and hairline. I would love a hairline like yours, mine is coming out in little patches on the front so if I have hair it looks weird. Yeah the cyst is gross, but go see a dermatologist and s/he'll recommend you something to help. In the mean time put some neosporine(spelling) on the cyst and then put a bandaid on it (or put two on and make and 'X').
As for the marks, put some acne stuff on your scalp, here I tell you what I bought some maximum strength acne medication (that's the name) from Target and its their brand. It's cheap and it works, trust me I use it on my scalp and forehead if I get acne, or have marks. I think its a bright green and white box, the tube is only 1 ounce so you might want to get two lol
Secondly I'm pretty sure your girlfriend didn't leave you because of your hairline receding, She was moving to London and I've heard of people splitting because they don't want to even attempt a long distance relationship. I mean you worry about the other person cheating, and you don't know their friends so you can't just ask. You have to always make room on certain nights to call them. And lastly you are not physically there both for the naughty (take a guess) or the nice (being a shoulder to cry on, being there to stick up for your significant other, being there so the other person can vent).
I don't know why she would block you on Facebook, maybe she was already seeing someone else. I know there are a lot of psycho boyfriends that start verbally abusing their ex when they find out they cheated. Yes she looks good, but dude you could get someone just as good if not better.
Now for your scalp, I have the same problem and I am not British I am just lazy and never leave the house. We are not the only ones though, a lot of the people on here that are bald by choice have pale looking scalp. I haven't tried it yet, but there are a bunch of people on here that recommend Jergen's Natural Glow moisturizer. I've seen little travel size bottles at Bartell Drugs, Walgreens, and Target (I don't know what stores you have in your are though. Bartells and Walgreens are pharmacy stores, and I'm guessing you'll know what Target is)
COME ON!! I thought you were going to look like this. I think once you get some sun, you'll be fine.

Same here! LOL