Welcome to the Rhino forum.
It is difficult to make suggestions without a .3dm file with the geometry and input used to create the geometry such as curves. You can upload a file by dragging it to where you type a post, or by clicking on the vertical arrow icon above where you type a post.
Also helpful is a description of how the model was created Based on the tags I assume NetworkSrf was used. That command can be very useful and is a favourite of new users, but it has some downsides. NetworkSrf frequently results in surfaces with many control points. Good models usually have close to the minimum number of control points needed to create the desired shape while conforming to any criteria. Fewer control points generally results in smoother surfaces and makes editing the surfaces much easier.