There are various types of birthmarks which are either pigmented (usually brown) or vascular ( red, pink, or purple). They are not hereditary and the cause is unknown, in most cases. To my knowledge they are actually less common in Philippines compared to UK.
Large pigmented birthmarks / "moles" may be pre-cancerous, in which case there is a clinical reason for removal (here, on the NHS). In most cases it's cosmetic (requiring private treatment). Surgery (with or without grafting) or laser treatment may be needed.
From your description clearly I can't say what kind of birthmark this is, nor advise on the cost of removal.
