Are you asking if it’s ok to paint the cable to match the colour of the wall , then Yes, it won’t harm the cable .
You should be able to paint over that small amount of damage, though if there a hole through the wall fill it first. If you do fill the hole make sure the filler is suitable for external use, for example, "SOUDAL REPAIR EXPRESS CEMENT & CONCRETE GREY". Make sure it has fully cured before sanding/painting.
Thank you for your help sounds complex I would have to get someone to do it as just my mum and I at home. Thank you for all your help and such reply.