Umbilical hernia?

So my son has had this little pinky sized bump above his belly button for a while now , he may have even born with it I’m really not sure but for the last few months it has been more noticeable he’s 18 months old , we switched doctors and I did make his new doctor aware of it she didn’t seem too concerned about it, she too measurements though and his next appointment is coming up and I’ll ask about it again of course I’m just wondering has anyone else dealt with this ? I know it doesn’t hurt him bcz when I touch it it doesn’t phase him .. I’m just getting stressed