Lemon juice is way, way too acidic a ph for human skin. It serves no theraputic function. Doesn't clean, treat or do anything other than to irritate your skin in some fashion. Don't use vinegar of any kind either unless it is massivlely diluted with water because same problem - way, way to acidic. It is also, as mentioned, a photosensitizer. No citrus oils or juices should ever be used anywhere you are exposed to sunlight.Hmmm...I'll take your word for it. Where I live, I don't have to worry very much about that.
Something I see a lot is people mentioning pores opening and closing. No. This cannot happen. Hot water or water vapour can soften and therefore lossen hardened sebum impacted in pore and help with its removal which is why facialists use steamers, but pores have no structure that makes them capable of opening and closing. They can look bigger if the skin's surface is rougher or if they are clogged with oil and skin debris, but you cannot make them bigger or reduce their size in any effective way.
The other thing I see repeated a lot is the idea that you can somehow make your skin produce more or less oil. No. Oil production is controlled by your adult sex hormones, which is why little kids don't get oily skin and acne and these problems only start with puberty and can extend through adult life until sex hormones drop off to lower levels post-menopause. When you overwash your skin your oil glands do not overproduce oil - what happens is the upper surface of your skin, those dead skin cells get dried out and roughened and the oil you do produce sits underneath or on top and it all feels awful and oiler, and sometimes inflammation can start from all the disruption to the skin barrier which can result in mic worse appearance, irritation, redness and the appearance of slightly oiler skin. But really oiliness is down to testosterone levels - this is why women with too much aka PCOS get acne a lot. It's why women who transition and take T often get way oiler skin and acne. It;'s why men usually have oiler skin than women and their products are a bit harsher than womens. It's why some types of contraceptive pill can resolve acne in some women because it's getting to the root of the oil production - hormones. There's too much emphasis put on topical products and routines as the way to control skin when the roots of a lot of acne issues is simply hormonal issues. Yes, how you take care of your skin helps a lot in appearance, but in some cases like serious under the skin inflammation the issue is beyond cosmetic routines.