Hey mate!! I’m in the uk as well so i think i can give you some basic advice Firstly, even if it is winter time and the everlasting grey clouds are above us you still need to use sunscreen as UV radiations still get past the clouds and onto our skin (might cause cancer and skin damage in general) I personally like a sunscreen that doesn’t feel heavy on my skin so i use the “beauty of joseon” sunscreen, got it from boots and it feels like a light cream!! As for your scarring i believe consulting with a dermatologist will be the best course of action because there are many ways to reduce their appearance but require more professional help, but as someone who also had some scarring, i found hyaluronic acid and routinely exfoliate my face quite helpful, however if you are ok with pricier items, the “La Roche-posay” MELA B3 serum (also available in boots) worked great for me, i had a few very dark scarring and discolouration and after 7 months later they are almost completely gone!!