You do not overfeed rescues. They can be very hungry, yes, but overfeeding them can cause serious harm. When snakes go to "feeding mode", they will eat, again and again, and it is your duty as keeper to think what is appropriate amount food at one time. Not to feed as much as they can take!

Fortunately your snake is not very emaciated, but looks like s/he is pretty dehydrated. Dehydration is a serious problem and can cause regurgitation if you start to feed too aggressively. If the snake vomits, you need to wait at least two weeks before next feed. Vomiting is not something to take lightly, especially when we are talking about animal in poor condition. Recovery takes time, you can't rush it.