I mean, if I'm wearing any makeup at all, even a tiny bit of concealer, you will know, because I will have made a giant fuss about how annoying it was and wondering if it looks okay. :P

But it would definitely be a good idea to offer to buy some as gifts, if she's interested in using it. (Honestly, he clearly has an idea of what kind of makeup he likes, if not necessarily the vocabulary to express it, so the two of them figuring it out together and then going shopping for it as a date is probably a good next step anyway.)