A number of theories are going around about ways that Christians can accept the Mark of the Beast and still escape punishment for doing so. They mostly centre around the "grace of God", and how a loving God would not punish anyone who says "Lord, Lord" to Jesus... whether or not they ever get around to even trying to obey him. But, of course, such a teaching is a perversion of the grace of God, and it makes a mockery of all that the Bible (and Jesus in particular) say about obedience.
It may well be that merely accepting the Mark (as the Revelation technically teaches ) is enough to land one in the lake of fire eternally, without any hope at all. However, what Jesus said in the Sermon on the Mount about cutting off your hand if it offends you (Matthew 5:30) at least presents a sobering picture of what would be the terms of a gracious "second chance"... if there is to be such a thing as a second chance.
The bottom line is that the longer one delays in obeying God, the harder it is going to be. Who knows for certain that there is not hope for repentance even in hell itself? But then who wants to go there to find out?
The Bible says, "Now is the accepted time. Today is the day of salvation. Today, if you hear his voice, do not harden your hearts as the Israelites did in the wilderness, thus provoking God's wrath." (II Corinthians 6:2, Hebrews 3:7-8, and Hebrews 3:15)