Chin up! Bethenny Frankel's Botox doctor reveals exactly what work the star has had done on her face and details everything you need to know about getting the injections 

• Bethenny, 45, told Dailymail.com she gets Botox injections in her jaw
• The SkinnyGirl mogul's dermatologist, Dr. Howard Sobel, explains how the treatment works to both soften the jaw and treat TMJ pain
• Dr. Sobel claims the Real Housewives star has not had cheek fillers

Last week, Bethenny Frankel, 45, admitted that while she has not had invasive plastic surgery, she does get Botox injections.

'I do look different. I’ve had Botox in my jaw,' she said at DailyMail.com's 2016 Newfront in New York City. 'You can see that my jaw has completely changed.' 

But can Botox alone really change a person's face that much? We sat down with Bethenny's doctor, Manhattan-based dermatologist Howard Sobel, MD, to get the skinny on the procedure.

About three years ago, Dr. Sobel suggested that Bethenny try Botox because her jaw was so tense due to clenching and grinding her teeth.

'When people clench their teeth, you can see the muscle in their jaw pop out,' Dr. Sobel explained. That's called the masseter muscle. And when they do it continually, that muscle builds up and squares off the jaw. Think if it like any other kind of muscle that would build up - like using weights to bulk up a bicep.'

For a feminine look though, you want a heart-shape jawline, not a squared-off one, said Dr. Sobel. 'You want the cheeks to stick out more than the jawline, but in Bethenny, it was the opposite.'

The benefits of injecting Botox into the masseter muscle are two-fold: It can help with the pain and discomfort associated with TMJ (temporomandibular joint disorder) and it can soften the look of the jawline.

Slowly, over the course of several months, Dr. Sobel injected small amounts of Botox into Bethenny's jaw. 

'It atrophied the muscle, which means she couldn't bite down as hard, and because she couldn't bite down as hard, the muscle got smaller and smaller, so the TMJ went away,' he said. 'But remarkably, her jawline was also no longer as pronounced. She didn't have the squared-off jawline, she had the heart-shaped jawline, which is great.'

At a certain point in the process, though, people began to speculate that Bethenny was using fillers in her cheeks.

'It was not that at all, though,' said Dr. Sobel. 'Nothing has been to the cheeks.' What people were seeing was a study in proportions. Before the injections, Bethenny's jawline stuck out further than her cheeks, but once the jawline receded, her cheeks appeared bigger because they now stuck out further - even though they were actually the same size they had always been.

Getting the right proportions took time. Bethenny wanted to be conservative about the Botox, said Dr. Sobel, which was the right approach. 'You have to work with it and tweak it. That's the key. And you don't just inject that masseter muscle and knock out it because you'll have trouble speaking and chewing and things like that. So it's little by little by little - and that's what we did with her.'

At last week's presentation, Bethenny said she was 'excited' by her new look, noting: 'I think it’s why I can take a shorter haircut.'

The star also revealed that she occasionally gets Botox injections elsewhere on her face to address wrinkles.

'I don’t do it religiously. Maybe once a year when I think of it, l’ll be like, Oh I look like a Shar Pei, let me do that.'