the question you have raised has to be answered in two parts
What is it
2. Do you require consultation.
MMR is given as a sub cutaneous injection. Meaning, it is not given in the muscle like other vaccines. It is just given below the skin. Then, skin bleeding can occur. That is what you have said as " a bit bruised", this will settle down on its own. This vaccine usually does not cause fever
and is pain less. But it is essential to take this vaccine.
Regarding consultation: Per se for this you need not take.
If there are bleeding evidence per other regions
skin bleeding at other places
joint painful swelling
Then only you need to consult. Of course they are not going to occur.
This is merely a normal variation