This is unlikely to be the result of your first surgery. In any case, if you'd like to avoid any extra scarring, you should speak with your plastic surgeon. They can open up your old abdominoplasty scar to allow access to repair your hernia so that the there will be no additional scar.
This is not uncommon and can be from diet and exercise changes after surgery as well as fluid retention from swelling. If concerned, review with your surgeon.
