elslok:
I don't think that it is self-destructive, but I doubt it will help; your mother is choosing to believe her husband rather than you and I believe she would find some way to discredit the results.
If you have to go to these lengths to "prove" something to someone, then, in my opinion, there are much deeper issues of trust. And if your mother is still listening to her husband, then he will manipulate the stories enough to convince her he is being truthful to her.
I know we all need our family in support of us, but sometimes we have to walk away and hope that things change within those we love and how they see things. It is not easy, but again, if you have to so all this, will your mother still believe you?
I would like to think she would, but I would also like to think she would have listened to you without the need for such.
All my best-
Refuse2quit

Thank you. A friend of mine says I am catastrophising at the moment as I have literally just reported him in the last few days and I found out that he has watered down what happened.

TRIGGER WARNING this is a little detailed.

I can remember him telling me to pull my pants down, I remember being sat on the bed and him kneeling in front of me. I know he inserted his finger into me and I remember him sitting back up and rubbing the mucus between his fingers, looking at it as he talked to me, explaining what it was. I remember this vividly. He has told my mother all he did was ask me to pull my knickers down so he could look and make sure everything was ok because I was panicking about discharge. It really upsets me that he could lie about it. Or rather lie by omission.

He'll say anything to evade exposure of his crime, and as a clever liar he sticks close to the truth. These people, child molesters, are SO convincing in their denials, and their crimes are so far outside the accepted norm, that we can begin to doubt our own reality. If your confidence starts to slip or you start to feel worn down, you can come here and tell the truth and you will be believed.

Unfortunately I had the same reaction as R2Q in terms of your mother. LuckyEmpath says her mother came around to believing her after a year, so perhaps yours will come around - but the abuser in that case was not her mother's husband. I hope your mother will come to accept the truth, but if she does, she will be exceptional.

The police will expect this though right? I mean I doubt any of the reported offenders hold their hands up and say "Fair cop guv!"

I would expect so! Keep us up to date on what happens, okay? I am very interested!

Polygraphs are very interesting devices. I have seen folks tell 100% the truth and the machine said they were ling, but my favorite, a guy who remained so calm and everything that he passed the test even though he was guilt...

I would hate to see you go in there totally ready to take this. And fail your own name or something. You sit right by the machine and you breath, it moves , you swallow it moves... You move even an inch it moves...
If they would determine that you were not truthful they might use that for him against you ..
Ah, lie detector test can't be used in the court house?
Yeah it can...

Please be very careful, I like the advice above that said if you have to prove anything, then there are more underlying issues of trust..

Been invited to the police station 1pm on Wednesday. This is getting very real very fast. Don't worry, not for a polygraph, just to make an official report following the initial one on Saturday.

I took a lie detector once - many years ago, when I was 18; I was one of those that could not pass the question about his own name, so I was determined to be "untestable". Being too nervous sets off the machine, as does any twitch, jerk or muscle contraction. I was as nervous as hell and failed every question, so my trust in lie detectors is pretty small.
But, I do hope that the police listen and take action. The man that abused you should be held accountable. Take care and let us know how things go.
All my best!
Refuse2quit