I took my friends daughters underwear
Really? That is something I have yet to encounter about anyone.
I wanted to see what they seem like up close.
Okay but this is not going to get you anywhere with that. Leave the undies where they are, make sure you just talk to people instead to find out about them without being sexually charged in any way. Lewdness is highly looked down upon, it can get you into a lot of trouble. I'm not trying to nag or critique you, but am worried for your state of mind.
My friend has always liked me and wanted me to have it.
I doubt this is the truth, just be safe and control the urge to take anything that seems immoral even if you have permission. It could be a trap of some sort to frame you.