Incidents like this are tough, really put your mind into overdrive with a fear factor. But you've had training about that sort of thing. You need to make a plan right now, how will you react when this happens again? Will you let it happen again? The best defense is a good offense. This is telling you that it's time to own this for all it's worth. You have to "know" that painting you nails is OK just because you want to and when you're asked about it again it's OK to say that. If you want to say more, say it like your the baddest girl in the room. Challenge them and make them feel the A Hole for questioning your right to authenticity. You're good at what you do, so they'll deal with it.
Had a call from a friend before Christmas, a neighbor had his tractor break at a very inopportune time, and since I'm the fix it guy out here my friend called and asked if I'd look at the part and see if I could get his neighbor running again. I said sure, bring the part over. I was upstairs when he showed up, my wife yelled up and I came out to the shop just expecting my friend to have a part in his hand. He knows I'm trans so I didn't think about my painted fingers and my T shirt (I'm a bit booby). Well, he wasn't alone and oops, too late! So I just went about things like there was nothing to discuss other than getting Henry's tractor going. Nothing was said, fixed his part better than new, shook hands and he so appreciated my work, and the fact I didn't want any money, just said Merry Christmas, that he invited me over for his New Years party (didn't go, was out of town). My friend said a comment was made that he noticed a few things, whats up, and my friend just said he hadn't noticed and it all went away.
I made up my mind, and it may take a while to get there for you, that I would refuse to be ashamed about who I was and that was the real coming out point for me. I told everyone, did it in a confident way that was matter of fact and made it clear that I was telling them because I respected them and wanted them to have the straight skinny. I made sure they knew that I was good with this. Really own this with no apologies and once you do you will find the experience liberating. And there are lots of us here for you as a Brother and a Sister. Toni