How painful is filler injection? Is it very painful?

I am considering fillers because I am concerned about my thin lips, but since I am a very timid person, my biggest worry is the pain.

I heard that the pain from fillers is more severe in the lips than in other areas because they are more sensitive.

I am wondering if applying anesthetic cream will make the filler pain almost imperceptible, or if I will have to endure a dull ache when the needle enters.

Would using a product containing a pain-relieving anesthetic definitely help alleviate filler pain? I look forward to hearing firsthand answers from those who have experienced whether the pain from filler procedures is severe.