Q&A for How to Build a Laser Pointer

Get a new (more powerful, more expensive) laser diode. They can be purchased on eBay and various Chinese sites (Banggoood, LightInTheBox, etc.).

It depends on the power of the laser, laser pointers like the one you will find in pens are mostly harmless unless you shine them in someone's eyes. Though burning lasers will burn you hand but a laser pointer is not that kind of laser.

The ideal battery should be reliable, rugged (doesn't break when you drop the thing), rechargeable (so you can keep using the pointer), capable of storing tons of power and match the voltage and amperage requirements of the diode.

Yes, but it's best not to let a laser beam touch your skin in one spot for a long time. It's possible that lengthy exposure in one spot could result in a slight burning sensation. (Of course, never point a laser beam at anyone's eyes.)