What do I do in this situation?

I, 17F, have had a recent dispute at work and it is really getting to me. I am usually the one to bite my tongue and get over it, after all I go with the 'you're at work to work, not make friends' sort of thing and I am terrible at speaking up about things without worrying that I'll get misunderstood or that I'll muddle up my words.

So, yesterday, I was with a colleague, who I will call 'L' and L was standing around doing nothing whilst I was serving out food. There was customers waiting and I had politely asked L to serve the customers, to which I got the response 'Why can't you do it?' To which I rolled my eyes and continued working.

Throughout the day, L had continued to make small yet snarky remarks, especially if I had made a mistake with an order.

What is the appropriate course of action without causing too much of a scene/drama?