I have the exact same thing. I asked my dentist he said it was normal and even showed me that he had one too.
It literally is just a bit of bone, dont worry!
As it does not hurt when your press it, it may be another tooth coming through (depends on your age).
If it was not there in March when you saw your dentist, and you are clearly worried about it, if it does not go away in the next few days or gets bigger, then make an appointment for your dentist to check it out.
Best wishes.