Hi. Without a more specific description we can't direct you to specific tools or options just can suggest learning using inkscape from the start and point to some tutorials instead.
What is the image?
An imported svg file, an svg with an embedded raster image,
a png/jped/gif/tif or other raster image
a dxf file or a pdf eps etc. ?
What do you mean removing some lines?
Are those lines only appearing on the rendering (=as on a raster image) or are they vector content? Are they part of a group, a pattern fill, clipped, etc. ?
Are you after a visual fix -"adding a white lick of paint atop", editing a raster image or hunting down some vector objects?
Can you share the svg file in question, the image in question, a screenshot in question, describe what have you tried, where you got stuck?