Subsequent to this reaction the positrons will annihilate with two electrons, adding a little to the energy. Note that every time a star manufactures a helium nucleus, it must make two neutrinos. Solar neutrinos - recent experiments have proven that detected neutrinos come from the direction of the Sun but that there are too few in proportion to the luminosity of the Sun. The apparent explanation is that the electron-type neutrinos produced in the Sun are mostly converted to undetectable varieties of neutrinos as they pass through the Sun. The life of a star.
Energy is lost , the proto-star contracts and heats up.
Eventually center becomes hot enough to overcome charge repulsion between protons. Hydrogen fuses into helium. This new energy balances the energy radiated away in the form of light. The star has now entered its main-sequence lifetime. The burning is regulated.