Swallowed my tongue piercing yesterday when drunk. i can't tell if the nausea i'm feeling is from being hungover or if it's caused by the piercing. really scared, what should i do?

Your nausea is most probably from being hungover. Your tongue piercing should pass without causing any internal damage since there really aren't any sharp edges. To be on the cautious side you may want to consult with a physician and have images taken to monitor the progress through your GI tract. more info: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3536040/

Nausea is likely from the hungover, do not replace the piercing, as you already experienced a scary event around it, cut down on alcohol, it affects your quality of life.

Your symptoms are from alcohol. Alcohol is a poison that never did anybody any good, ever, so stay away from it. It will destroy your brain cells, facilitate development of cancer in many organs, including breast, cause hepatitis, cirrhosis and pancreatitis etc. There is no safe level of alcohol intake. Quit while you are ahead.