i need advice for my rescued python

[chezza]

hi.i would like some advice please.. a couple of weeks ago i rescued a snake from someone.. i instantly felt sorry for her the minute i saw her.. she is a 7 foot carpet python.. she was in a box of around 2 foot long with no heating, nothing at all.. when i went to collect her, the bloke had fed her a live rat about 10 minutes before i got to her.. i was discusted.. the rat had bitten her through the nose and tail.. i took her home and got her cleaned up and she is now in a lovely warm viv.. sadly last night, the end of her tail fell off.. as much as we tried to save it. we have noticed her body is covered with scars.. she has obviously ate live before and this man told me she ate live for the first time that day.. i know hes lying.we had to clean her mouth today as she had an infection.. her nose is slightly blocked with dried blood.. is there a way to help her unblock it? she opens her mouth alot.. im sad because she is such a lovely snake.. she is getting use to us now and knows shes loved.. she obviously has not had a life before.. also her skin is very dull and dark at the top of her body. we thought it was dirt but its not.. why is this do you think? she has no vibrance to her what so ever.. she is not due shedding as i know how my other snakes look when shedding.. her all round look is extremly dull.. i feel sick she has been mistreated.. i love her to bits and would like some advice please.. thankyou.