Easy,
Yeah no worries man, BTW have fab time away!! I frequent Europe and Asia mainly but I'd love the chance to go stateside sometime. I get the feeling your abit of a product junkie dude. Only say that coz I am or should I say was until I found works for me and sometimes using too much stuff can really be counter productive.
U know alot of the stuff u want to look at should still be available to u, on the high street certainly online anyway. Tell u what, try doing something like this say for a week or 2 weeks tops when u get back and I'm sure this should help some. You say u don't shave every day which in this case'll help u abit., You'll probably be doing most of this anyway but
Wash your head every evening with good scalp wash that doesn't contain salicylic acid but can really get the grease/dirt off you skin. Something like Head & Shoulders for men or the new Oxy face wash for men which u can get I dunno in Tescos or SuperDrugs.
After drying, apply your salicylic treatment, Anthony Logistics gel, St Ives or whatever. Certainly when your not shaving, your skin heals if its sensitive to putting a razor on it so it's be good to apply something like this.
Just for the first week or so, using a very slick shave gel that caters for sensitive scalps, Bald Guys would be good, shave with the grain only. Again less blades like in an M3, HB or even an Excel still works sweet and is less irritating. Make sure you allow your head to heat up good with lots of hot water prep so all the pores are open.
Don't bother with the salicylic treatment after shaving just quickly wash, rinse with really cold water or rub a cube and apply your moisturizer if u need it.
I'm convinced this should pretty quickly at the very least stop this up down flare ups your having and if it calms down sufficiently, do against the grain, maybe add a good oil to make it really slippy if u think that'll help and hopefully the salicylic treatment u can whittle down just 2/3 time a week.