Remove the stem from the pears. Using a wooden skewer, make a hole in the stem end of each pear. Insert a lollipop stick in each hole.
In a double boiler or a heatproof bowl set over a pan of simmering water, melt white chocolate. Let stand until cool. Dip the pears in the chocolate, turning to coat. Stand the pears up in a piece of foam or oasis. Let stand until set, about 40 minutes.
In a heatproof bowl set over a pan of simmering water, melt the semisweet chocolate. Let cool for 5 minutes. Fit a small pastry bag with a #4 tip, and fill with melted semisweet chocolate. Pipe chocolate onto pears to create facial features. Let stand until set, about 10 minutes.