I have been in your shoes too many times before....having to go to work or out with friends with a big breakout...it's a lousy feeling. Honestly, what I usually do is try to stay home and not see anyone for a day to let my skin heal a little. A day usually makes it a little better but it is important that you DO NOT spend that day over-washing or over-treating those spots. Wash your face, apply your topicals and then LEAVE YOUR FACE ALONE! It will only make it worse if you pick at it or irritate it in any other way. Drink lots of water, take your vitamins try not to stress about it. Your face WILL heal.
As far as letting friends know, I usually just say that I am not feeling well and just need to stay home in bed. You don't have to tell your friends if you don't feel comfortable and they should understand if you just need a day to rest.
Just keep thinking about this as a temporary condition....try to think positively and remember that your friend and family love you for who you are, not your skin. Most importantly, you need to remember that you are still YOU, with or without an occasional bad breakout.
It happens....it sucks....and it will go away eventually. Keep your chin up.