In urgent need of help - obsessive skin picking

Hey guys,

so I've been picking my skin (mainly on my legs) for about a year now and my thighs and buttocks especially look AWFUL! I'm supposed to go to a wellness centre with my bf and some colleagues over the weekend and we're obviously gonna be wearing swimsuits. So, I really need to cover the dark spots and scars on my legs with something that will last in the swimming pool as well.

Basically, my legs are COVERED in newer/older dark spots (red fading into dark brown/grey) - there's like 50 of them per 10cm square. What should I use? I'm a complete make-up noob.

Also, what do you think of these two ideas:

1. applying some of that white liquid stuff, I think it's called calamine lotion onto the spots, let it dry, then apply self-tanning cream on the rest of the skin (essentially all over my legs, but it wouldn't get to the spots obviously).
2. Sunbathing with very strong sunscreen applied only to the dark spots.

Obviously, these are more long-term solutions, but I also need advice for the weekend, so any suggestions are welcome!

Thanks in advance! <3