Honesty is Like a New Car
The moment you drive a new car off the lot, it immediately begins losing value. The same applies to the truth. Sometimes being totally honest is hard, and we try to delay awkwardness or hurt by only telling a portion of the truth.
Honesty decreases in value every day. Telling the whole truth a month late is nowhere near as valuable as the first day you knew it. Delaying honesty can stifle a personal relationship, and cause issues the workplace.
Thinking it will hurt less later is an illusion. Then you will deal with telling the truth and explaining why you waited. Don't let time degrade its value, give the whole truth before you even drive off the lot.