A persistent nightly fever despite taking a Monobact injection suggests the current treatment may not be targeting the root cause. This can happen if the underlying infection is viral, fungal, resistant to this specific antibiotic, or due to a non-infectious condition. Do not switch medications or start alternative treatments on your own. You need an immediate medical re-evaluation, including blood tests or cultures, to determine the exact cause of your fever. Please contact your prescribing doctor urgently for an accurate diagnosis and a revised treatment plan.