Belly button indentation after EON

I have done two rounds of EON in my abdomen and am very happy with the results. However, I have noticed that after the first session, and more so after my second round, an indentation has been forming around my belly button. It is relatively mild, but it's still fairly obvious. I have a BMI of 23 and am 30 with no skin laxity issues. Has that happened to other EON patients? The staff placed a small circular sticker on my belly button for each session. Should each EON segment be spaced out?