Tips on finding a specific doll? (MSD MIISHA

I'm looking for a Msd miisha (fairy head one) 

It's been really hard I think, need help lol feeling hopeless but strangely dedicated to it..

For resin BJDs, I'd recommend checking Den of Angels.  Their Marketplace is pretty busy, and they're also fairly strict about proof of authenticity, since I know recasts have become a big problem. It may be listed as MSD F-12 as well, since that was the FCS number.

Tracking down that head in particular is going to be pretty difficult, however, since it was discontinued in 2007. What you may want to consider is seeing if you can have another head modified to resemble Miisha. For vinyl dolls, I'd say the DDH-12 looks pretty similar, at least as a starting point.