It could be an inflamed tastebud. (Kind of doubtful since it isn't painful though.)
It could be oral thrush (an oral yeast infection).
It could be oral herpes that you didn't realize you had contracted a few weeks (months, or years) ago. Just now popping up from the friction of last night.
It could be a number of STDs or STIs that were contracted previous to this particular incident. You can contract things like herpes through kissing even so keep it in mind.
Your best bet is to call your doctor today. Today, as in, right now. And make an appointment to get it checked out.
If it's thrush then you might need antibiotics to get rid of it or you can pass it onto your partner or end up with some really, really nasty side-effects in your mouth.
If it's an STD then you'll need to get treatment. If there is no treatment, then you'll know so that you can decrease chances of passing it along to your partner.
See your doctor today. Go on and give them a call and explain about the weird thing on your tongue that you want to get checked out. They can make a quick appointment to do a little scraping on it to see if it is anything at all.
We can't really give you a for-sure answer. We aren't able to sit down and check this out at all angles. We can't scrape off a few of the cells for testing. Heck, we're not even doctors. We wouldn't even know what we were doing if we were able to examine the issue ;)
Attention: NOTHING on this site may be reproduced in any fashion whatsoever without explicit consent (in writing) of the owner of said material, unless otherwise stated on the page where the content originated. Search engines are free to index and cache our content. Users who post their account names or personal information in their questions have no expectation of privacy beyond that point for anything they disclose. Questions are otherwise considered anonymous to the general public.