There are not "ugly" people. There is bad lighting.
Well, there are several things to consider. I am just making a list, but you need to take a dive into each of them.
You can make an interesting portrait giving some context. I do not mind a scar at all, probably it is due to a hazardous environment... what if you take a photo on that environment.
Arguably the most important thing on a portrait. Most likely diffuser size angle and contrast, to mention some elements.
Help your client look the way they are meant to look.
Choose the best option for the occasion.
Here we are on the major leagues. This is not a theoretical situation, it is about people. You are the one making decisions on the portrait... so MAKE decisions and communicate them.
The attitude is beyond posing, it is a fantasy land where the interaction between you, your model, the imagination and all the previous elements fuse together...
You are not a photographer... you are the director.
I want to add that this attitude is given by the confidence and trust you inspire on your subject. They are relying upon you are taking the best possible shot.
- And some photoshop will not hurt.
You need to go way deeper. For example, my basic search terms can be "portrait photography light" but if you type "sports portrait photography light" you get a new world of configurations. You need to explore and practice.