Please recommend a cost-effective ampoule for sensitive/oily skin with bumpy acne.

I have oily, sensitive skin with small bumps (milia)! I'm writing this post because I'm having trouble deciding which ampoule to use these days. Since I'm a student, I don't have a lot of money yet, so please recommend a serum or ampoule that is affordable and good for small bumps. I'd prefer a low-irritation ampoule, and a hydrating one would be even better. Currently, I'm using the Mediheal Madecassoside Blemish Serum, and it seems to prevent breakouts rather than get rid of them... However, since I do have some acne, I'd like a product that is really effective..!! Oh, and I've noticed that Houttuynia cordata products seem to suit me well (like the Abib Houttuynia cordata Toner Pads).