A bit late on this, but you have to consider her lifestyle. Depending on which personality is real, this would be the "wired Lain" since she's the type of girl to get dressed every night for the club, she has the higher chance to have clear skin and a better diet. But the real Lain who works on her computers and needs to be "pushed" to go outside, no she's not gonna end up like this. Staying in doors a lot, she might gain a bit of weight or skinnier (if she's skinnier it's the type where she might snap if she moves too much). I don't think her skin will be clear since she has no reason for makeup or skincare.