What's the best way to reduce swelling in your face?

It depends on what caused the swelling.

If it was trauma from a blow or from dental work, use ice packs to the site for 15-20 minutes every 1-2 hours while awake. If you are on no other medication that contradict, you can use some ibuprofen or Aleve for the swelling too.

Swelling is inflammation so using an anti-inflammatory like ibuprofen or Aleve (Naproxen) can help.

Don't discount the power of ice though. Ice can really help to reduce swelling and inflammation.

If you don't see a reduction in the swelling after 24 hours then you need to be seen by a medical professional.