Regarding having a bad temper, ask God to help you have a gentle spirit.
"Be angry, and yet do not sin; do not let the sun go down on your anger, and do not give the devil an opportunity" (Ephesians 4:26-27).
Anger can easily lead to hate.
Jesus said we need to be careful to not be angry:
"You have heard that the ancients were told, ‘You shall not commit murder’ and ‘Whoever commits murder shall be liable to the court’. But I say to you that everyone who is angry with his brother shall be guilty before the court; and whoever says to his brother, ‘You good-for-nothing’, shall be guilty before the supreme court; and whoever says, ‘You fool’, shall be guilty enough to go into the fiery hell." (Matthew 5:21-22)
Furthermore the Bible says:
"Everyone who hates his brother is a murderer; and you know that no murderer has eternal life abiding in him." (1 John 3:15)
See also Galatians 5:19-21.
So it is important to overcome anger, wrath, and hate. Anyone who is continually angry is not a true believer.
Many Christians think all they have to do is believe in Jesus. But believing without repentance or acting according to one's belief is false belief.
Therefore, if we have any sins we know of, we need to work with God diligently to overcome them. As long as you are working with God to overcome sin, then you would not be in trouble.
This is what you can do:
1. Pray to God to help you have a gentle spirit. Pray to God to help you not get angry.
2. When you are in a situation and feel yourself about to sin, try to walk away from the situation and not think about doing things in your mind that is bad. Rely on God to not think about hate or vengeance.
There is no magic to overcoming sin. With all diligence, try your best to obey God. With 100% God's help and 100% your diligence, you can overcome any sin. You may still fall sometimes, but keep PRACTICING and PRAYING, and God will give you a way of escape.