how can we use toner and astringentboth at a same time?

Question

I HAVE A OILY SKIN

Answer 1

Astringent is always drying.
Toner is, sometimes, unless formulated for dry skin.
You don't need both. If you do use both, you will probavly get flaky spots, without improvement in your problem areas.
Use cleanser, toner or astringent, sunscreen and moisturizer for YOUR skin type. Clean, tone, and sunscreen in AM;
clean, tone, and moisturize in PM. Use a exfoliating face scrub 2-3 times a week.