Easier said than done, but you should work on self acceptance. As others have already said, your skin looks great. If you wore a good moisturizer and a thin layer of silicone based foundation primer, just on its own, it would help to soften any texture. I have the same problem with textured skin on my forehead that would hardly constitute as actual scarring, and primer does wonders.
If they are mild then yes needling will make a difference, but I personally don't think it's worth it to get it done professionally considering how much each session typically costs. I would purchase a 1.5 mm derma stamp (don't get a derma roller) and use it every 4-6 weeks. You'll want to do do a lot of research on pre and after care. Keep in mind that all collagen induction treatments take time. It will take several months at least to see improvement. Take lots of pictures to track your progress.
Factoid is right about TCA peels. They won't do much except help with overall texture and anti-aging. Assuming your scarring is more than superficial, your best bet is probably subcision and suctioning, then perhaps micro needling again just to help even out the texture. Also, you should be taking a lot of pictures of your skin to track progression, otherwise you may not be noticing improvement.
Personally, I think derma rollers carry more risk than benefits due to the way they penetrate the skin and create micro trenches. Derma stamping is safer and more effective in the long run, but micro needling in general is meant for very superficial scarring.
Early stages of rosacea. It sounds like heat is a trigger for your flushing (it is for most people). As others have suggested, laser treatments like v beam are often used and very effective for reducing flushing and baseline redness. If it's very mild, at home red light therapy is also another option but takes a while to see results (6 weeks+). There are tutorials online on how to make your own device which is actually what I've done. Most devices online are way overpriced and use parts that are relatively cheap to purchase and assemble yourself. Moisturizing well and being extremely gentle with your skin is also very important, and whatever you do, do NOT use the product Mirvaso. It causes severe rebound redness in most that use it and can permanently worsen rosacea.
If it happened around the time you burned your skin it's probably related to that. Did the burn leave a scar or something or has it just been persistently red since then? I don't think vitamin D deficiency has anything to do with although that can cause a host of other issues so it's important you get your levels up ASAP.
Inflammation often makes pore appear larger, whether it's from retin-a, bp, certain scar treatments etc. It often happens when you first start using retin-a ,for example, and don't give your skin time to adjust. My skin was red, flaky and inflamed with large pores until my skin adjusted to it. There are also skin conditions like rosacea that can cause orange peel like textured skin.
Are you currently using a moisturizer? It sounds like you need to be moisturizing more than you currently are if your skin is that dry and flaky. My skin looked awful when I first started using tretinoin and I had the same experience you did. It went away after my skin adjusted to using it about 6 weeks later.
How long has it been since you used it? Do you have a good quality picture that shows the orange peel texture? I highly doubt this is anything permanent, but it does sound like your skin is persistently inflamed if it's dry and scaly. That itself accentuates any pores making them appear larger.
To the OP, I'm really sorry you suffered acne for so long and definitely feel for you...but the others are right. I tried natural and homeopathic remedies for acne and scars for years out of desperation and was left angry and upset every time time. Sometimes I would get temporary "improvements" that were entirely coincidental, and then I'd be back to square one. No one here is trying to spread hate but to help you to understand that this is not only physiologically impossible to improve scarring but also risky. The good news is that there are plenty of effective non-aggressive treatments for both PIH and scarring but this isn't one of them.
Microdermabrasion is kind of joke to be honest. Subcision plus suction is your best bet, and then some kind of resurfacing treatment to really tighten and smooth any remaining texture. As others have said, it's possible to get 70% + improvement, but it's also important to keep your expectations realistic. I think subcision and suctioning would give you great results.