From the sound of it your little ones leg might be broken/strained/etc....the best thing I would suggest is bringing your beardie to the vet. If not, at least make a cast for your little one, or at MINIMUM do the foam portion of the cast.
As for opening and closing of the mouth, thats normal...just means your beardies hot. Bandit does it all the time and eventually he moves to the cool side of the tank. Sometimes I will spray him with some cool, not cold, water to help lower his temperature and keep him hydrated.
Also, as for the cast falling off...thats pretty normal. I had to recast bandit several times. The reason it falls off is because the cast is on tight enough to create support, but not so tight as to cut off circulation. So no worries.
In between re-casts, make sure to give your beardie a bath. That will take off whatever gets crammed in the cast and keep the skin healthy.
Keep us posted! Sorry I did not see earlier!!! Feel free to ask anything, small or big. Hop your little one feels better!
hey guys thanks again for the input and support, heh and i guess your right she just got hot. shes doing a lot better now walking with both back legs just after a few days when i carry her though she doesnt like to grip my hand using the bad leg unless she has to so i suppose its still healing, btw i thought maybe it would slow down her growth needed to heal and all but i was waay wrong. shes getting big fast and its scaring me because the other beardie is not. i dont know if maybe females grow quicker or something? iv had to switch over to theese moist Bites food for them because the amount of crickets i need to buy for the cost.