Do I have an underbite or weak chin? My upper lip looks receded compared to my bottom lip. (Photo)

Thank you for your question.In order to determine whether you've got an underbite, I would need to see your occlusion. Looking at your profile view, you've certainly got a small chin (microgenia) which sits posteriorly (retrognathia).Assumimg that you have a normal occlusion or did not wish to undergo orthognathic surgery, a genioplasty will most certainly give you an excellent result.Hope that helps.Kind regards,Ivo Gwanmesia London Plastic Surgeon (UK)

 To make the diagnosis of an under bite requires dental x-rays. From the one limited photograph, there's a weak and recessive chin profile for which a chin implant can augment  the chin forward to help with facial balance and proportions. 

It could be both weak chin and jaw issue. It is hard to tell without evaluating the teeth and xrays. But in your case you could probably get away with just a chin surgery.