I have rosacea too, peterpie, & can get very self-conscious about it when it's flaring - though less so than when I first developed it 5 years ago.
I know from experience that the redness is just about the hardest symptom to treat. It's quite irritating when people blithely point out that there are treatments available - actually, the only licensed medications for rosacea are effective for the spots that some sufferers have, not the redness / flushing. Laser treatments / IPL can work, but I haven't had that much success, & they're not available on the NHS.
It's also much harder to find make-up that works for rosacea as people who have it tend to have very sensitive skin. I use a zinc oxide based sunblock that's also tinted & covers up the worst of it - on a good day, anyway - but have to order it from the US. It's called elta md uv physical SPF 41, & I would recommend it.
My sons are a bit older than yours, peterpie, & they do know I have sensitive skin - haven't bored them with the technical details, but I can't tolerate chlorinated water, for instance, so dh always has to take them swimming, so I have felt the need to give a brief explanation. They know my skin gets "sore" & just accept it really.
To be honest, I don't think most people think much about other people's skin - I mean, they notice if it looks red, but probably not in a judgemental way, just as a sort of fact. I notice people's skin problems more since I developed rosacea, but it's made me aware that not many people really have perfect skin - a lot of people worry about spots, or large pores, or whatever. I try not to focus on it too much & definitely avoid things like looking in mirrors too much when I'm flaring!
I used to make more of an effort to hide my rosacea when I first had it but I think that made me feel worse about it in a way - like I had to disguise myself to be fit for human consumption! I try to be more matter of fact about it now - I will refer to it if necessary (like if someone asks why I can't drink alcohol, which gives me hideous prolonged flushing).
Try not to be too upset about what your son said - as other people have pointed out, children do just say these things & probably point out other features that we & other people have - it's just that we tend to take the comments more personally if it's something that really bothers us. My sons have pointed out that I have a long neck but couldn't care less about that!!