Following recipes to the letter doesn't always mean a perfect result for someone's particular palate. Enchilada sauce that is tame enough for some might tip the scale into fiery for others. You may have gotten hold of some absolutely potent chili powder--the primary heat source in enchilada sauce--or just misread the recipe and added tablespoons instead of teaspoons. In any case, it's possible to fix a four-alarm enchilada sauce. With too much heat, cooks often use sugar, dairy or citrus to calm things down. The type of food you use depends on the dish itself and the result you want.
Keep the enchilada sauce warm so it doesn't begin to thicken. This will make blending in the citrus juice more effective.
Add the lemon or lime juice, one teaspoon at a time, to the sauce while whisking continuously.
Taste after each adjustment before adding more juice. You may want to ask someone else to give it a taste, or cleanse your palate before you try the sauce again.
If you don't have lemon juice or want to try a different texture, add sour cream or even plain yogurt into the sauce. This can cool it down while making a creamier sauce.