Demi Lovato is in a war of words with a one pissed-off tattoo artist!

Last week the popstar posted that she was going to get rid of her "vagina tattoo" which was actually a pair of lips she got back in 2011.

Well apparently the tattoo artist who originally inked Demi was a woman named Ashley McMullen -- and she saw the post and was none too thrilled about the diss. So McMullen thought it wise to take to social media to explain her side of the story -- and shame Lovato.

Here's what the disgruntled "artist" had to say:
    "Cool post @ddlovato, thanks for getting the tattoo covered up I did for free that you specifically asked for. Not to mention you didn't even have the courtesy to offer me any money in the first place. You pissed all over our toilet seat and you made a fool of yourself. What a shame that people look up to you. The tattoo you covered it with kinda sucks too. Looks like you might forever be a goon." She added loads of hashtags to fuel to the fire, including, "#demilovato #scumbag #turd #claimstobesober #drankallthebeer #peepeetoiletseat #yousuck"


But that wasn't all McMullen had to say:
    "It's a really nice example to people your setting saying to not do drugs, but honestly you were acting like a full time slob. I can not believe you would have the nerve to post this when you didn't even pay for the tattoo or offer me any money at all. Yes fans, I did the original and it is not my fault you wanted a pair of red lips on your wrist next to your upside down tattoo. Unfortunately this one is not very good either. Talking trash makes you look bad, girl. For the record, I'll be posting my story until I get an apology. You never even gave me a shout out after I dealt with your drunk ass… And you peed on our toilet seat. I have many that can couch for that. Grow up lovato!"


You can "couch" for it? Good one. We aren't sure exactly why McMullen would want to take credit for shorty work that Lovato anonymously slammed or why she would publicly admit to tattooing a drunk teenage -- and the "Heart Attack" singer seemed perplexed too.

The singer hit back:
    "First, I would like to say I'm really sorry I don't remember you or getting tattooed by you, but as you know I was fucked up and sometimes people act like '#turds' when they're loaded. Second, I apologize for my '#peepeetoiletseat'… That wasn't on purpose, I was simply a drunken teenage girl. Lastly, I apologize for making fun of your work.. But… if I were you, I wouldn't claim that one because it looked more like an open v*gina (or even a butt hole as my 8 year old little sister called it at the time.) I also wouldn't be admitting to the fact that you tattooed a very intoxicated 18 year old on a tour bus without the proper judgement that most legit tattoo artists have of saying 'Hmm… This underage kid is wasted, maybe I shouldn't permanently ink a hot pink kiss mark on this girl's wrist….? Oh well… F*ck it, she's famous.'"


But Lovato was just getting started. The 22-year-old old continued:
    "I can't blame you for getting the tattoo, I take full responsibility for that but if the issue here is you wanting credit, maybe next time you should wait for the person to get your tattoo sober so they would actually remember getting the tattoo in the first place, or perhaps you could've thought about all of this as a blessing that I forgot everything about you - that was until you outted yourself for the now internationally infamous 'vagina tattoo.' But you're right, I should give credit where credit is due, and you Ashley, surely deserve credit for this one. 👏👏👏😂😂😂 #justputitonmytab"


Boom! And that's the drop the mic moment.