Like Tom, I think the grey spots are "cold" -aka not enough cure mixture, and the pink spots are "hot" -those spots that did get cured.
Also like Tom I do not think it's normal and would chuck it. Live and learn.
The cure has to be carefully measured based on trimmed weight, the meat has to be evenly coated with the cure, laid smoothly in the bag - no wrinkles, and the meat has to be turned daily. A brine will form in the bag which should not be removed - simply leave it in the bag and turn it daily to reabsorb over time.
Here's an easy side meat bacon recipe
http://tvwbb.com/showthread.php?13312-Bacon-made-easy
And this is Shooters’ Dry Cure Recipe for Buckboard Bacon:
Cure Mix:
1 TBS Morton’s Tender Quick per pound of trimmed meat
1 tsp Raw Sugar per pound of meat
Mix and combine well with the above cure. Remember that all must be used on each cut to ensure the proper and safe amount of cure. If multiple meat cuts are used it must be mixed for each individual cut.
Spice Mix:
Mix the following per pound of trimmed meat.
1/4 tsp Cayenne Pepper
1 tsp Basil dried
1 tsp Onion Powder
1 tsp Garlic Powder
1 tsp Hungarian Paprika
1 tsp Course Black Pepper
Rub meat well with mixture and place in zip lock bag. Any remaining rub left behind should be scraped into bag. Place bag in refrigerator turning bag over daily. The temperature of your refrigerator should be below 40 degrees but above 33 degrees. The meat will feel firm when cured. Remove meat from bag after curing, rinse, and place uncovered in refrigerator overnight or until dry. Fry a thin center cut slice and if to salty rinse again in cold water for 1-2 hrs, changing water every 20 minutes. A few quartered raw potatoes in the water will absorb salt quickly. Dry again and smoke to internal temp of 140.You must cook before serving.
Note: If you smoke to an internal temp of 160 you may eat uncooked. You may glaze during the smoking process with honey, mustard, or maple syrup, if desired.
Curing times:
You should figure 1 day cure time per ¼ inch from center of meat out. In other words measure the total thickness of the meat and divide by 2. Divide this result by 0.25. The result of this is the minimum number of days suggested to cure.
It is a fantastic recipe.