Lip fillers are the injection of filler material into one or both lips using a needle. The most common Harley Street lip fillers used are hyaluronic acid, collagen, and fat, though most lip fillers of today are made of hyaluronic acid or ingredients similar to hyaluronic acid." Why? 

Hyaluronic acid is a naturally-occurring substance in our bodies and is used often in skincare products and dermatologic procedures such as lip fillers because it can help skin retain moisture. 

Hyaluronic acid is the go-to choice for that look, and dermatologists also like it because it is very well-tolerated among patients. If you’re considering lip filler for the first time make sure that the doctor does lip filler extensively and is a master injector who knows how to avoid and handle complications.

Your practitioner will probably start with a numbing gel on the injection area, and the injectable itself typically contains lidocaine, which is a local anesthetic. Depending on the area and treatment type, it can take up to two weeks for swelling and bruising to completely disappear, though most of it typically dissipates within 24 to 48 hours.

If you're unhappy with your outcome, hyaluronic acid fillers can easily be removed if you wish—your practitioner will inject an enzyme that dissolves the filler.