hi parry,
well, you mentioned your injury as grade 2, let me just explain so that you are sure;
grade 2 hamstring strain/injury is explained as moderate tearing of muscle fibers with pain generally covering a larger area than the 1st degree strain (pain often localized with one finger). stiffness and weakness will be felt and the painful area may appear black/blue due to bleeding within the injured muscle. significant limping may also occur when walking.
now regarding your query, let me give you a short note on the pathophysiology so that you understand better. generally when a muscle gets injured (grade 2, in your case) there is bleeding within the injured muscle. a chain of events take place before full healing
a. inflammatory phase b. fibroblastic phase and finally c. maturation/remodelling process.
the noticeable bulge you mentioned is the fibroblastic tissue. fibrosis in other words is very much like scar tissue formation.
generally with time and conditioning exercises your muscle will be perfectly fine, back to normal. you will have problems only if there is a mismatch - every muscle in the human body has a length:tension ratio. following an injury the muscle might lengthen or shorten due to fibroblastic activity and can lead to problems, weakness etc. as far as you are concerned, I dont think there is any lack of strength/weakness etc. so just be cool, forget about the bulge and go ahead with your regular training.
all the best.
cheers,
thomas