"I gotta get my rest on so I can get my face where it's supposed to be ..." he added.
Bieber revealed he's working on facial exercises to get back to health.
Ramsay Hunt syndrome is a rare neurological disorder characterised by facial palsy, or paralysis, often accompanied by a rash affecting the ear or mouth. According to the National Organisation for Rare Disorders, an estimated five out of every 100,000 people in the US will develop RHS annually.
The syndrome, first described in 1907 by Dr James Ramsay Hunt, is caused by an infection of the varicella-zoster virus — the same one that causes chickenpox and shingles, which means anyone who has suffered either of those illnesses could also come down with RHS.
Symptoms of Ramsay Hunt syndrome
Most RHS cases result in some degree of facial palsy, as well as a blistering, often painful rash that affects the outer area of the ear and canal — though both symptoms do not necessarily present in all cases, nor in tandem. In some, only facial paralysis occurs, requiring a blood test to confirm the presence of VZV. In others, the visible inflammation may also spread to the patient's soft palate and throat. Other notable side effects include tinnitus, ear pain, and some hearing loss and, more rarely, amplified hearing, vertigo, nausea, loss of taste, dry mouth and dry eyes, the New York Post reports.
Lyme disease
In January 2020, Bieber revealed he had been battling Lyme disease.
The disease can be spread to humans by infected ticks and causes symptoms like tiredness, aches and loss of energy, that can last for years.
Bieber broke the news again via Instagram, writing: "While a lot of people kept saying Justin Bieber looks like s**t, on meth etc. they failed to realize [sic] I've been recently diagnosed with Lyme disease."
He added: "It's been a rough couple of years but I'm getting the right treatment that will help treat this so far incurable disease and I will be back and better than ever."
Bieber found the disease had a big impact on his mental health.
He revealed to his fans he had "been struggling a lot" and "just feeling super disconnected and weird."
At the same time as his Lyme disease battle, Bieber suffered from a "serious case" of Epstein-Barr virus, commonly known as mono.
Depression
In a YouTube docuseries, Justin Bieber: Seasons, he opened up more about his mental health issues.
He spoke about how he hit rock bottom, which left him "really, really suicidal" and in "constant pain."
After the success of his debut album Baby and his mega-hit of the same name, Bieber struggled to cope with global fame.
He said: "Being an entertainer can be very self-serving if you let it, because everyone is screaming for you and you've got to constantly go back to the 'Why? Why am I singing for all these people? Is it because I want to feel good about myself? Or to make others feel good about themselves?'"
However, he did not suffer from any major symptoms and was quickly back on the road.
Injuries
Bieber is a keen skateboarder, and while he's showing off his skills, some stunts have turned into painful incidents.
In 2014, he was filmed falling to the pavement as he tried out some tricks in New York.
Hailey's stroke
In March this year, Hailey suffered a blood clot in her brain which caused her to suffer a transient ischaemic attack (TIA) also known as a ministroke.
The model described the incident as "the scariest moment of her life" as she lost the ability to speak and her face started drooping.
Doctors at UCLA later told her that she had a grade 5 PFO (patent foramen ovale), which is a hole in the heart.