What if we have already done many bad things? Can we ask the Buddha to forgive us?
The Buddha is considered our Teacher and not someone that we pray to for forgiveness. Buddhists do not believe in any external agencies that we must ask forgiveness from, or worship for salvation.
If Buddhists were to ask for forgiveness, it would be to the person that we wronged, and not to a third party or external agency. If it were not possible to be forgiven by the person we wronged or to make amends, then we should let the matter go, learn from it and forgive ourselves, of course provided that we are sincere about it.
The Buddha teaches us that we are each responsible for our own actions, and that we are each capable of shaping our own destinies. We should thus consider carefully before doing anything wrong, and instead try to do right at all times.
If you are unsure whether an action is right or wrong, you can apply this simple rule of thumb as taught by the Buddha : if the action harms either yourself or another, or both; then avoid doing that action. If not, then go right on ahead!
Source: Just be Good