Forehead vs. Right Hand
You will either receive the mark in your forehead, or in your right hand.
And he causeth all, both small and great, rich and poor, free and bond, to receive a mark in their right hand, or in their foreheads.
- Revelation 13:16 (KJV)
The forehead is symbolic of your mind (just think decisions, frontal lobe, etc).
The right hand is symbolic for actions (just think enforcement, coercion, etc).
Here are some quotes to think about.
To receive the mark of the beast in the forehead is, we understand, to give the assent of the mind and judgment to his authority in the adoption of that institution which constitutes the mark. By parity of reasoning, to receive it in the hand would be to signify allegiance by some outward act.
- Uriah Smith, Daniel and the Revelation, p. 623/624
The devil doesn't care whether he convinces you intellectually to follow the beast or whether he forces or coerces you to follow with the symbol of the hand. God never uses force or coercion. He only uses choice.
- Adventist Review
The bible makes a distinction on those who received the mark of the beast in the hand and those who received in their forehead. In their hand, just means that they know the truth but are compromising their position due to fear etc. In their forehead, they totally rejected the truth of the Seventh Day Sabbath and there is no compromising in their hatred against the truth of the day.
- Lisa Audain, Thusia SDA
God never forces the will or the conscience; but Satan's constant resort-to gain control of those whom he cannot otherwise seduce-is compulsion by cruelty. Through fear or force he endeavors to rule the conscience and to secure homage to himself. To accomplish this, he works through both religious and secular authorities, moving them to the enforcement of human laws in defiance of the law of God.
- Ellen White, The Great Controversy, p. 591
Summary
In short, if you agree with the change in God's Law, then you will receive the mark in your forehead, but if satan somehow forces you to keep the Sunday (by penalties, or not being able to "buy or sell"), then you will receive the mark in your right hand. Either way, you receive the mark.
Trust and obey is the only way.