I've heard that getting Botox just above the upper lip can help to "lift" the lip a bit to create a more prominent pout? (photo)

Nothing very good happens when botox is injected into the lips.  Sure, it will soften issues you may have but at the price of function.  Don't do this to yourself. You also don't need Nova threads in your lips. Your lips are wonderful.  A small lip filler treatment would enhance the lips - less is more.  Avoid the so-called smooth fillers for this service like Juvederm, Belotero, or Restylane silk.  These products are helpful for hapless injectors but they tend to drift after the fact and can cause the dreaded lip shelf.  I personally very much like Restylane for the lip edge.

If you find an expert injector, Botox can give you a subtle upper-lip lift. However, Botox only lasts three to four months. It's also essential to find someone who has done this procedure before, as the lip must continue to be functional despite the fact that some of the muscles have been relaxed.
 
I would actually suggest using one of the hyaluronic acid fillers, as your upper lip is not quite at the ideal proportion that we like to see in relation to the lower lip (i.e., 2:3). The filler will also make your lip slightly more visible when you smile; Botox alone won't be able to accomplish that. I hope this helps.

The risk of placing Botox in the upper lip for "lift" may actually create the opposite effect. There are several elevator muscles that surround the circular shaped lip muscle (orbicularis oris) that can become paralyzed if the Botox reaches these muscles. It sounds like the kind of results that you are seeking would best be resolved with lip fillers. You mention that you want more prominence and pout.... both of these can easily be accomplished with well placed (and amount) of lip fillers to give a very natural appearance. A filler called Volbella is excellent for highlighting the lip border and anatomy.  

Injecting Botox into upper lip can actually create more pout but one has to be very careful since too much Botox will actually dropo your lip and make it paralyzed
Another way to create more pout is a lift lip procedure - increasingly popular operation performed under local anesthesia. It actually permanently changes shape of your lip with minimal recovery

Yes, what you've read is correct. However, the goal is to be conservative. Anything more than 4-5 units placed at the vermillion border can cause drooling and other issues with lip competence. I add Botox to the upper lip for both lines and wrinkles and increase red lip show. However, some patients do not like it. Start slowly with a small amount of Botox to determine if this is correct for you. Also, consult with a facial injectable/ surgery expert who understands the complexity of the muscles around the mouth area and will treat you with a soft touch.Stephen Weber MD, FACS