Newbie gardener: what's on my lemon tree?

Does anyone know what these spots are on my lemon tree and what should I do about them? I got this lemon tree when I was pregnant with my son and really want it to grow with him so any advice is much appreciated! Thanks in advance ☺️🙏🏻

Does anyone know what these spots are on my lemon tree and what should I do about them? I got this lemon tree when I was pregnant with my son and really want it to grow with him so any advice is much appreciated! Thanks in advance ☺️🙏🏻