Side effects of eyebrow waxing?

I'm a 23 year old man with Mediterranean genes which means I have very thick, hairy, black eyebrows (think Eugene Levy). I've gone eyebrow waxing 4 times, once every 3-4 weeks. I don't get the arched, drag queen eyebrows, just a little grooming so I don't look so scary lol. and I think they look a lot better after the treatment but I'm worried about any side effects. Is it true that waxing pulls the skin and makes it sag? Also, does the waxed hair always grow back the same thickness, or will it thin out over time? I'm a bit of a cheapo so I don't want to keep paying for eyebrow treatments until I'm 60.