According to our current understanding of physics, a photon does not accelerate to the speed of light after it comes into existence. Photons are elementary particles and, by definition, they always travel at the speed of light in a vacuum.
In the framework of special relativity, the speed of light is considered to be a fundamental constant of nature, denoted by 'c.' It is the maximum speed at which information or causality can propagate through spacetime. Photons, as particles of light, travel at this maximum speed as soon as they are emitted or created.
It's important to note that photons do not experience time as we do. From their perspective, if it were possible to have one, they would "experience" their entire existence instantaneously, since time does not pass for an object traveling at the speed of light. This concept is a consequence of the time dilation predicted by special relativity.
So, to summarize, a photon does not need to accelerate to the speed of light after it comes into existence because it is always moving at that speed as soon as it is created.