Illness/Sickness: Growth on side of axolotls stomach

[Axelotal]

I got back home from a holiday a few days ago and noticed a bubbles like bump on the side of my axolotls stomach area, which appears to be a growth. I have no idea what this is or if its a big concern or not, any help would be greatly appreciated, thanks.

 

[Hayleyy]

Are you able to attach a picture? If you click the paperclip while writing a reply you can pop one in straight from your computer/phone. Also post your water parameters too
Did you have someone taking care of the axolotl while you were away?