@ddljohn-- I'm sure it will be fine, as long as it doesn't have any other ingredients that might aggravate oily skin. I've heard that vitamin C helps fade blemishes and many of us with oily skin have old acne marks, so that's a great idea.
I would also recommend serum with ylang ylang. I've been using it for the past two weeks and like it very much. It's a very soothing serum.
You might also want to read some product reviews before you invest in a serum because it can be kind of expensive.