Do you tip the makeup artists at Clinique?

I use Clinique products and buy them at the Clinique counter at Macy's. Today my hairdresser accidentally burned me while fixing my hair for a party tonight. It's not a bad burn, but turned dark purple. I called Clinique because I know that they do makeup and asked if they had anyone who could help. They said that they did and to come down at 2:00. I went there and this girl did full makeup... it took an hour and a half! The part that I feel bad about is that I've only had my makeup done at MAC before, where there is a minimum purchase. Not so at Clinique... it's free! I don't carry cash with me, but I felt like I should give the makeup artist at least $20 for doing such a great job. I thanked her over and over, and when I was going to buy the gloss that she used on me, she told me no and gave me a tester. She said I should try it out for the night and see if I still like it. Do the girls at Clinique take tips? I feel so awful that I didn't have anything to offer her.