Don't panic and don't restart the schedule. Reconstituted rabies vaccine kept at room temperature for a few hours is generally still potent, so treat that 3rd dose as valid and just complete day 28 on time. If you want certainty, get a rabies antibody titre 2-3 weeks after the last dose - a titre above 0.5 IU/ml means you are protected, and only then would a booster be considered. Watch the scratch site for spreading redness or pus, and report at once for any tingling at the wound, difficulty swallowing or fear of water. Happy to review your schedule on a Practo consult if you want it double-checked.
Next Steps
Complete the day-28 dose on schedule; check rabies antibody titre 2-3 weeks after the last dose if you want confirmation.