Make up for lost time
Definition 1 of 2
Pro Tip 1/3Context Matters
Used when urgency is required to recover time that was lost due to earlier delays or setbacks. 
The team worked overtime to make up for lost time after the project delays.
Pro Tip 2/3Expression of Regret
Can imply regret for not being efficient earlier and the determination to be more productive now. 
He studied all weekend to make up for lost time on his thesis.
Pro Tip 3/3Not Literally
The phrase isn't about turning back time, but about intensifying efforts now. 
After her illness, Mara doubled her training sessions to make up for lost time.