What I think you may well have is the skin of the head of your penis has become intolerant to either particular chemicals placed on it, or potentially, just about anything placed on it. If this is the case, the unprotected sex was just a part of the process of your skin becoming intolerant,
So, the bumps are naturally present on the head of the penis, only, we do not usually notice them, it is when the skin on the head of the penis becomes sufficiently irritated that they become noticeable.
What I suggest will happen for you is that if you continue as you currently are the bumps will simply remain visible.
What you need to think about is everything that comes into contact with the skin on the head of your penis - this can be something as simple as soap, shower gel, other body wash, such as if you use hair shampoo in the shower and some gets onto the skin of your penis. Also, many men use Lubes of different kinds for masturbation and sex, these can be specific lubes, but many men use stuff like Baby Oil or skin cream as a lube, or regularly apply a skin cream to hydrate the skin of the penis.
What you need to do is to exclude anything such as this from getting onto your penis. Wash your penis with water only and make sure it is completely dry afterwards.
This will be an extended process as you may not see any change for 3, 4 or even 6 months or more of excluding all these chemical based items from getting onto the head of your penis …