Massachusetts law requires that all cars have insurance on them with the minimum limits of $20,000/$40,000 for bodily injury and $5000 for property damage.
Compulsory motor vehicle liability insurance is discussed in chapter 90: Section 34J of the MA legislature laws. Here it states that being without insurance on a motor vehicle is punished by a fine not less than $500 nor more than $5000 or by imprisonment for not more than 1 year or both the fine and jail time.
The law goes on to say that any person convicted of being uninsured shall be liable for the amount greater of $500 or 1 year's premium for compulsory motor vehicle insurance for the highest rated territory and class or risk in effect at the time of the commission of the offense.
A person cited for driving without insurance may also have their driver's license suspended for 60 days by the Registry of Motor Vehicles and likely their registration and tags to the vehicle suspended as well.
You can read through Chapter 90 of the MA legislature to see exactly what the extra penalties may be since you were involved in an accident without insurance. Likely they will include you being held liable personally for the damages you caused and for you to show proof of insurance when it is time to reinstate your license.
Under the Safe Driver Insurance Plan you will also be issued a surcharge of 3 or 4 points since you were more than 50% at-fault. It will depend upon the amount of damages done, since you say it was a fender bender than the amount might be under $2000 and thus only 3 points.
For a quote on Massachusetts automobile insurance click here.