Definitely shouldn't be doing this. If a lead acid battery is left to discharge significantly the plates will form a layer of sulphate on them which will render the battery unusable. It is practically impossible - certainly beyond the ability of ordinary mortals - to recover a battery from this condition. One of the side effects of this is that the plates swell! Probably this is why the ends of your battery are bulging out. Take it back to where you bought it and see if you can get another one. It should have been in a good state of charge when you bought it and, although it will have lost some charge over the 6 to 8 weeks you've had it, and might need to go on a charger before it would crank an engine, it should not have degenerated to the extent of swelling out the battery casing in that time. I keep a large 80 amp hour battery in my garage for jump starting which lives connected to a ctek smart charger all the time. It's now at least 6 years old and still going strong.
Be very careful what your'e doing with it wont you? The case will be quite stressed if the ends are bulging to any great degree and could rupture. The last thing you want is a large volume of sulphuric acid dumped inside your car, in your house, on you or your clothes, etc, etc.