I had chin/jaw fillers, can bits be dissolved to reshape or will it dissolve all of the filler? (photos)

For unique cases where a variety of modalities could be used to treat the condition, I would suggest an in-person or virtual consultation to develop a custom and effective treatment plan. It is difficult to precisely define the best option without collecting the same information. I suggest reaching out to an expert for a consultation with surgical and non-surgical methods to get a comprehensive option. Best, Dr. Emer.

From your photos I can see what you are referring too. The issue is your previous injector only injected your chin from the bottom and not the sides. It seems they also did not do the pre jowl area. It looks like your back of your jawline was done from the sides and this has added width to your face. It would not be as noticeable if the pre jowl area had been done. My first recommendation would be to do your masseters (facial slimming) this would help give your face the V Heart Shape look and help slim the face. Next we need to add a small amount of filler to the pre jowl area to balance the back of the jawline and lastly we need to do some chin filler from the sides which would help give the chin a more heart shaped appearance. At the moment the chin is too square and therefore looks masculine rather than feminine.

First of all, it depends on the type of filler you received, but let's assume for the sake of this message, it was one of the HA fillers.  You can dissolve them, but it's not exact.  Unlike the filler placement which one can do fairly precisely, the product used to dissolve the filler is not precise.  Basically, you should expect to lose pretty much all of the filler in that area. You may not, but you should even attempt this unless you are prepared to "erase" it all.  

you are correct from your photo your chin does look to long.
 You may need to go back to your doctor and get some of the filler dissolved in her chin.
To make your face more heart shaped looking at your photo you would benefit from mid face filler such as Juvederm voluma ( this lasts upto 2 years).This will lift any jowl you may have.. I cant tell if you do actually have a double chin but filler doesnot really disguise a double chin. If you truly have a double chin then Australia now has an injectable product which permanently dissolves the fat under your chin.
I hope this help you