Wow! Hershey's likes you! Multiple congrats!
You said you are not sure if there is a limit, and the rules don't state that there is. They only say that you cannot continue to play if you have won a grand prize, so it looks like you may continue to play as you are a first prize winner (four times over!!).
"PRIZES: Twenty-Five (25) Grand Prizes. Each Grand Prize consists of $2,500 HERSHEYS BLISS Cash awarded in the form of a check (made payable to winner). Approximate retail value (ARV): $2,500.00 each. Twenty-Five Thousand (25,000) First Prizes. Each First Prize consists of a coupon valued up to $3.99, good towards the purchase of one (1) bag of HERSHEYS BLISS Chocolates. Limit one (1) Grand Prize per person/address/household. If you win a Grand Prize, you should not continue to play. Odds of winning depend on the random time at which prize is available and on time a particular participant submits a play. The number of prizes available will decrease as the game progresses. Total ARV of prizes awarded is $162,250.00."