If I was going to make a suggestion, I would say to remove the damage from picking up the bullet entirely, but make the bullet impart (some of) its momentum onto the player when they pick it up and only apply damage if that momentum forces them into a wall/enemy.
I never encountered a situation where a bullet, fully charged or not, dealt more than one damage, which given how many hits the enemies take and how much longer it takes to safely recover a charged bullet over an uncharged one; made it much easier to use uncharged bullets over charged bullets.
The core issue I had with recovering the bullet was that:
- it seemed to take way too long for the bullet to lose its "hot" status.
- picking it up early didn't communicate that I was losing health, so I thought there was a "trick" to picking up earlier, such as approaching it from behind or from the side. This resulted in the bullet sometimes getting picked up without incident and sometimes it would just mysteriously kill me (though I imagine all these scenarios I was just losing health without realizing the health loss scaled with the bullet's "heat").