important question about bump on testicle

Im 13 and a half years old and a while ago i noticed a small bump on my right testicle. When i would check at random times, it would be visible, and then there were times when i couldnt even see it at all. Now, for the past few days, it seems to have disappeared but could this mean it maybe "navigated" or went somewhere else? I also think my testicles have gotten a bit larger, but could that be because of puberty?