Umbilical hernia repair with mesh 4 weeks ago. For the last 1.5 weeks I've felt a lump in the same place as before. Recurrence?

As title says, umbilical hernia repair 4 weeks ago with mesh. I've felt the lump back for the last 1.5 weeks. Feels the same as pre-surgery. Looks normal though other than the lump as if I never had surgery. It goes in and out if i press it. The pain is very minimal. Is it a recurrence or something else? I called the surgeon he says not to worry but I feel like that's what they always say...