An attorney repping Tessica's management team fired off a cease and desist letter to the person who appears to run the IG and Twitter accounts @gossipofthecity_ -- telling them to stop spreading the claim TB hustled everybody into thinking she sprayed Gorilla Glue into her hair.

The account has been posting about it for several days now, including messages and videos to both accounts -- which have close to 610,000 combined followers -- insisting Tessica is a liar and that she pulled a fast one ... especially on those who donated money to her.

The account even re-posted a 15-minute video from another woman who claimed to have sprayed Gorilla Glue in her own hair, trying to debunk Tessica's account. The post read, "Salute to this sister who actually deserves the money y’all donated to that liar. #girlbye."

To that, Tessica's lawyer says her predicament was neither contrived nor a joke, and to suggest otherwise is wrong. Her attorney, Jeffrey Klein, says Gossip of the City is defaming Tessica and warns the account's operator that they're on thin ice.

You can read the letter for yourself ... it's clear that a lawsuit could be filed if the account keeps it up. We're told this letter was sent last Friday -- yet, most of the posts still seem to be live as of now.

@gossipofthecity_ even acknowledged the cease and desist in a separate post, calling it a fake. We've been assured by Tessica's team, though, that it is very much real ... and they mean business.

Now, Tessica herself detailed the pain, embarrassment and agony she was going through with us directly on 'TMZ Live' -- and insisted this was as real (and unfortunate) as one could imagine. Remember, she went to the ER over this, and even flew out to Cali for a procedure to remove the adhesive.