Is giving a tattoo with ink pen ink safe? what could happen?

Ink poisoning perhaps.

The kind of ink that you use in an ink pen is not intended to be put under the skin. Worst case scenario, your body might not respond well to the chemicals in the ink, and everyone responds to things differently. You could just have a superficial reaction, or a system-wide one. Best case scenario, you're going to have a crappy looking tattoo that will be seriously faded within a year. Beyond any issues that your body might have with the ink, getting home made tattoos just aren't safe. You could get any number of infections from not using sterile needles. And you probably aren't going to be happy with the results. Its best to spend the money and get it professionally done ... its relatively safe and painless, and will stay beautiful for the rest of your life if you take care of it.

i know someone who had a freind that was alergic to the ink that she used for a tatoo and she was seriosly sick she had to get it removed even heaing it was painful

Blood poisoning -sepsis - lose a limb or death unless treated