CRJ200 First Officer reported a pack malfunction and cabin pressure warning during climb out. Flight crew donned oxygen masks and returned to departure airport safely.

Narrative

Upon climb out the Captain called a R High Pack Temp and decided to continue due to a time threat. As we continued through 10;000ft the Captain transferred the radios and pulled out the QRH from there we reached 14;000ft and the cabin alt EICAS message turned to a warning message we decided to promptly level off and advise ATC that we were [requesting priority handling]. We began a descent dawned our O2 masks and the Captain continued with the qrh we leveled at 9000ft and completed the QRH procedure. Meanwhile as the pilot flying I began to set up the aircraft to return to the airport while complying with ATC instructions. We determined the treat was no longer a factor but needed to return to the airport as quickly as possible. After completing the set up we ran landing numbers and realized we had an overweight landing and noted that as another threat to the situation. As a crew we advised ATC we were ready to return to the airport and completed a safe landing. The emergency vehicles completed an inspection and found the aircraft was safe to return to the gate.Cause: Mechanical Malfunction Suggestions: After discussing the event as a crew there was only a few things we could have handled differently. We forgot there was a QRC procedure but the Captain decided that we had already started the QRH and there was no time to take a step backwards as the situation was being handled. I also forgot to squwak XXXX