Facebook eventually filed for an initial public offering on February 1, 2012. Facebook held an initial public offering on May 17, 2012, negotiating a share price of US$38. The company was valued at $104 billion, the largest valuation to date for a newly listed public company.
No one knows what causes these small, painful blisters inside your mouth. Triggers include hypersensitivity, infection, hormones, stress, and not getting enough of some vitamins. Also called aphthous ulcers, canker sores can show up on the tongue, cheek, even your gums.
Mouth ulcers are caused by many disorders. These include: 1  Canker sores. 2  Gingivostomatitis. 3  Herpes simplex (fever blister). 4  Leukoplakia. 5  Oral cancer. 6  Oral lichen planus.