Hello
Yes of course these can be refilled. Any dental treatment that you get done you need to visit for a follow-up every 6 months because fillings generally have a tendency to get dislodged from the margins. This is known as microleakage. So you need to visit your dentist, he or she will examine the tooth, clear the decayed portion of the tooth and do a refilling. It is better to go for a laser composite tooth colored filling.
Next Steps
kindly visit your dentist and get the treatment done
Health Tips
Don't ignore it as the decay might become deeper leading to sensitivity and pain subsequently.