Keep my skin young

New to skincare, in early twenties.

I started exfoliating a few months ago after spots, red and painful to the touch, started appearing more often on and around my forehead (nodules or papules I think). I have an oily t-zone and although my routine has helped massively, I still have blemishes and darker areas of skin left by spots.

My nightcare routine works well with Nivea q10 energy rarely breaking me out (so long as it is not applied too liberally), but my day cream often leaves my skin greasy and less smooth. Tiny bumps appear which are visible close up in the mirror but are too small to really feel physically. Cosrx products have helped with this but I would still like to get rid of the small indentations and discoloration left by spots or at least make new imperfections less common. I have never tried serums or toners but am open to suggestions.

I would also like to keep away fine forehead lines which currently become more apparent after raising eyebrows to put contact lenses in. Would you recommend derma rolling for this and are there any rollers in particular you would recommend?

My price range is anything but high end, ideally ~£15 a product or less, but I am open to spending more on products that will last a long time.

Thanks in advance