The summer before last, I went to Nowon to get Botox for my temporalis muscles and square jaw again, and also got a Shurink treatment at the same time.
Everyone at the clinic was kind, and I remember the total came out to a little over 300,000 won. For Shurink, some people say it hurts, but honestly, for me it hurt less than getting scrubbed at a bathhouse, and it was just slightly prickly.
As for the effect... This goes for both Botox and Shurink, but I do not recommend it unless you plan to keep getting treatments regularly. For Botox, the actual effect lasts 3-4 months, and for Shurink, I did it with expectations after watching YouTube, but it was not noticeable.
If you have financial leeway, it is fine to do it, but I would not really recommend it to job seekers like me.