[65Bowrider]

I agree that you need to find the "cause" of the bulge.
Is the boat sitting properly on the trailer with proper supports?
If the cause is not obvious, then a suggestion would be to off-load the boat onto the ground, a flat 1x4, laying on a flat surface (concrete slab). Lightly supported at the chine to keep from tipping over. Keep checking the supports & keep them barely touching.
Let the boat sit for a week or two to 'relax' out, and see if the bulge goes away.
We did this with our 21, and she became perfectly plumb and level. Hope this helps.