When to Go to Confession?

Whether a lie or our anger is a mortal sin depends upon their severity. Lying that I did not leave the bathroom light on would be a venial sin. Lying about a murder would be a mortal sin.  In the same way, a brief fleeting anger wouldn’t be a mortal sin, but a deep-seated anger could very well be a mortal sin.

You would need to examine your conscience and what the potential consequences of your lies or anger might have been.  However, a good rule of thumb would be: when in doubt, confess it. Your confessor can help you with a spiritual assessment.