COSRX The Vitamin C 23 Serum, bought with my own money

I'm not saying this product is the worst, it's just that Vitamin C serums don't seem to suit me.

It stings a lot when you use it, is difficult to manage, and you have to apply it only at night.

The expiration date is really short at only a month, and it has to be refrigerated, so it's really hard to manage.

And if you store it even slightly incorrectly, it oxidizes immediately like that and you have to throw it away...

As someone with oily skin, the Vitamin C serum seems too greasy for me, so it doesn't seem to suit me at all.