Hey,
I'd say try to do some pinkie exercises, You don't have to buy a book to do it, invent some of your own, and find out which one works. I often do staccato pinkie scales.. perhaps some dotted rhythms, just semiquaver with dotted quaver rhythms, do those 20 bars like that, also, try to use your thumb as a pivot, and just do short notes on the little finger, try to get a bouncing action going.... I hope this helps, if it doesn't, ask your teacher for some advice.
About not getting nervous for exams, I'm sure you'll hear the just relax, and picture the examiner in some funny costume, if picturing them nude will send you into spew... be confident, play like he/her isn't in the room, get into a calm status before you even go into the room, and just don't think about it too much, the more you do the less you're likely to concerntrate on playing.. Hope that helps.
Ludwig