Came out in a rash , itchy, burning

Before l lashed out a purchased this serum l made my own vitamin c serum which burnt my skin quite badly cleared up in a week , so l thought l would buy skinceuticals ce ferulic , after my first use l had exactly the same reaction, so if your thinking about buying this serum l would buy some ascorbic acid power mix a tiny bit with sterile water and see if you have a reaction, most review site only say positive things about this product , l have tried to give reviews but they don't publish them ,