Do you think that those in hell can go to heaven if they change their ways?
I don't believe that there has been any revelation or teaching that mankind can advance after their judgement, however, silence does not make it absolute. In scripture it often uses the phrase eternal damnation but the revelations of Joseph Smith say the following:
Doctrine and Covenants 19:5-15
5 Wherefore, I revoke not the judgments which I shall pass, but woes shall go forth, weeping, wailing and gnashing of teeth, yea, to those who are found on my left hand.
6 Nevertheless, it is not written that there shall be no end to this torment, but it is written
endless torment.
7 Again, it is written
eternal damnation; wherefore it is more express than other scriptures, that it might work upon the hearts of the children of men, altogether for my name’s glory.
8 Wherefore, I will explain unto you this mystery, for it is meet unto you to know even as mine apostles.
9 I speak unto you that are chosen in this thing, even as one, that you may enter into my rest.
10 For, behold, the mystery of godliness, how great is it! For, behold, I am endless, and the punishment which is given from my hand is endless punishment, for Endless is my name. Wherefore—
11 Eternal punishment is God’s punishment.
12 Endless punishment is God’s punishment.
13 Wherefore, I command you to repent, and keep the commandments which you have received by the hand of my servant Joseph Smith, Jun., in my name;
14 And it is by my almighty power that you have received them;
15 Therefore I command you to repent—repent, lest I smite you by the rod of my mouth, and by my wrath, and by my anger, and your sufferings be sore—how sore you know not, how exquisite you know not, yea, how hard to bear you know not.