Greetings heparin-based ointments like Thrombophob in 45-day-old infants is not universally established, and professional guidance is essential. Monitor the injection site for any unusual redness, swelling, or skin irritation. . Alternative post-vaccination care typically includes gentle cold compresses or infant-safe pain relievers as directed by a doctor

If you don’t see any new development or change locally it should not cause worry. In fact no need to apply anything. But no worries if only small quantity is applied.

Yes you should not apply in 45 days because it cause Allergic rashes over that area but luckily your kid didn't had that . So next time onwards don't apply

Consult with Pediatrician physically for further evaluation and treatment

If Thrombophob ointment was applied only externally on the injection site once or a few times, it is very unlikely to cause any harm to your 45-day-old baby. The main concern with such ointments in young infants is that they are generally not routinely recommended because safety data in very young babies is limited, not because a single application is known to cause serious problems.