I have rosacea and it’s quite annoying 
You usually get prescribed antibiotics for it but no one seems to really know why they help. And then it comes back anyway. So I really want to get to the bottom of it and hack it! I didn’t have it all my life so I’m convinced it’s something about my current lifestyle/environment that caused it.
Does anyone have any experience of the sort of experiments I should be running on myself to get to the bottom of it?
it’s complicated 
There are tons of factors that can influence skin conditions: anything in your diet, allergens, stress levels, the amount and quality of sleep you get, cosmetics, even clothing.
Try to get as many of these as constant from day to day as possible, then attack one group of factors. For example, two months ago I ran a strict Whole 30 trial and my skin cleared up to point where I and others notice (unprompted).
Once you get results, change one single variable at a time. For instance, reintroduced dairy for a week, but keep everything else (not just diet, but all other factors) the same, and see what happens. Nothing? Great - dairy is OK for you. Continue by reintroducing sugar, etc.
Hello,
Good directions above ^^
Also there are topical solutions as well. Usually skin washes, and creams containing sea kelp, also digesting these specific certain substances consitently, and illiminating others from diet and epidermis contact, though this must be a dedicated practice if one is to see exemplary results.
That would be a good first step if you choose to not take antibiotics to cure it longterm. For instance drinking calendula tea and digesting and eating the tea leaves, as well as bathing with a pure calendula soap works in coparison to alternatives, it is a natural antiseptic. You can find calendula soap that is organic, etc. These things really work, though not traditional and alternative to pharmaceutics.
You may want to do a rule out for origins/causes.
Good luck!