I had a similar problem with a MoHo that I owned a few years ago. There were smoll holes in the dash where the PO had fastened a shelf and a couple of small tears. I called a few auto body shops and one had a service that they used to do these type of repairs. When it was done, the blemished litterally were gone, unless you know where they were and you looked really hard at the area. The color and texture match was perfect. You might try that if you are looking for a professional results.
Otherwise, any auto store sells a vinyl repair kit. You mix the liquids to match the color, then apply it to the dash, add a texture patch that matches what you have (these are in the kit) and pass a low watt heat plate (also provided in the better kits) to cure it. This works well also, but you have to practice on scrap a few times to get it right before you are ready for prime-time