moles are harder to tattoo, as the skin texture is different. I'm not sure if a liver spot would be, I'd have to ask one of my brothers (I worked in the shop for 2 1/2 years, but NOT as an artist, can't draw a straight line with a ruler and map!!) To tell if the spot is dangerous, you'd be best speaking to your doctor or a dermatologist. I just had several moles removed about 6 months ago (mostly for cosmetic reasons, and none were precancerous), and was surprised with how knowlegable my GP was, so it would never hurt to ask! You could also keep an eye out for free skin cancer screenings in your area (around me the local hospital system does them twice a year).
If you get the okay from the docs, I say go for it! Tattoos hurt, but not too bad, kinda like a brush burn. Believe me, if they hurt too bad, I wouldn't have as many :rofl: Below is my left forearm a week after wek finished the first piece of the coverup (we're covering the third tattoo he ever did, the black and gray vine, he HATES it now). There's a whole lot more now, pic is 2 years old, it's a work in progress (it'll eventually be the whole arm). If you notice, in the middle pic, the botton leaf has a "blank" spot, that's a mole we left alone.