"Please borrow a pen from your friend."
I was thinking ペンの友だち, but I guess that would be "Please borrow your friend's pen" which is slightly different.
I think this is the first time I've encountered から meaning "from". As well as it meaning "because" and "since" in recent lessons... So much to remember!
I hate apples? 私はりんごが嫌い（きらい）です。 With 嫌（いや）します you'll be misunderstood. It sounds like 癒します(いやします), 'to heal' (dictionary form is いやす).
Ni is the direction of a movement, kara the origin. You would use ni to lend something TO a person (xにかす), and kara to borrow FROM somone (xからかりる)