Red Skin with White Spots on My Sim

my Sim currently has this too.
If your Sim is a different color and blotchy, check the bottom left of your screen and you will see the ailment name. Have the Sim open their phone under "Home" and choose Visit Naturopath. It costs 1,500. 
I decided not to cure him, to see what would happen. He is vomiting a lot in the toilet, but gnomes are cleaning my apartment. 

It is the Gnome Lure ailmentzentax234​ 

Literally got that now

thanks! ill try that!

Here's a list of ailments and apothecary cures.

https://www.ign.com/wikis/the-sims-4/Ailments_and_Cures

This is one of the ailments that come with Enchanted by Nature. 

There are several means how to fix it:

• Use your phone to visit a naturopath. (It costs 1500 simoleons, though.)
• Ask a fairy to cure you. (They don't always oblige.)
• Make your own cure at an apothecary table.