Mama, for anything concerning foot and mouth disease especially if it's affecting your child, please see a doctor or go to your nearest health center right away, they'll know exactly what to prescribe and where to source it locally or through proper channels. Hindi ito dapat i-delay lalo na kung may symptoms na.
I understand you're frustrated with stocks, pero honestly, ang best move talaga ay makipag-ugnayan sa inyong barangay health center o LGU, they usually have access to medications na wala sa regular pharmacies, or matutulungan ka nila mag-source ng tama at safe na gamot. A few of my mum friends have dealt with similar situations, and the health workers really came through for them! Sana mabilis kayo mahanap ng solusyon. Sending you strength, nak.