Underarm fat?

Idk how to get rid of this fat. It makes me very embarrassed when I wear sleeveless outfits or tanks or whatever and it makes me self conscious. Any idea how to get rid of it.
And I go to kickboxing so I work out my arms a lot. I've had this since I was a child and I was a super fat kid. I mean I was like 115-120 when I was in the third grade so yea lol. But please help I'm open to all suggestions.
Thank you so much in advance !!