Do you mean the little white dots on the gills? It's hard to tell, but it may be the start of a fungus.
If you put your axie into a container and gently try to 'brush' off the spots with a cotton bud (q-tip) you might be able to dislodge it. If it doesn't come off, or returns I would salt-bath your axie.
(I actually removed a small spot of fungus on one of my axies with a small, soft paintbrush, it worked for me!)
Keep us updated on how your axie is getting on.
By the way, if you check your water parameters, including temperature, it may be something slightly out that has caused the fungus (if that's what it is).