Typically UX designers don't do visual designs, although the visual side of your product takes a huge part in the user experience. This sounds a bit contraversial so it's always good to have a good general feel of aesthetics.
There are 4 possible cases in the intersection of visual and ux design:
- A product can have really bad UX with amazing visual design: non-intuitive interface with plenty of usability issues.
- A product can have really good UX with poorer visual design: really slick and intuitive interface.
- A really bad product consist of poor UX and visual design as well.
- An amazing product has really great UX and visual design.
This doesn't mean that UX designers must have amazing visual design skills as most of the team design is a team effort: you'd need a great UI (visual) designer who can lead the visual design.
To make your design look aesthetically appealing.