Crack in the paint – what to do?

Hello dear forum, since my idea of cars is limited to driving, I wanted to ask you for advice. I have for the first time a self-inflicted damage to the car. Stupidly this accident hit me 4 weeks after the purchase of my new Tucson and not before it with my ancient peugeot. Anyway, there was a smaller collision with an object where it broke the underrun protection. Due to the force is also a crack in the paint next to the daytime running light unscathed Now to my questions: 1) Does such a deep crack have to be painted and what happens if I have the crack repaired only slightly (must not be perfect). is there a risk of consequential damage such as rust etc.? 2) is only the damage itself painted or the whole area? I am concerned that one can recognize clear color differences to the newly painted area (color sand white) I was in 3 workshops, 2 of which want to paint the area and a advises to leave the crack so, since it will hardly be visible after the replacement of the plastic parts and lacquered areas always show color differences. As I said, it is about a new car (3000km). I look forward to your input. Thank you in advance for your advice many greetings