薬を飲み始めると、すぐに痛みなどの症状はとれてきますが、すぐに潰瘍がなおるわけではありません。

、、。

Once you start taking medicine, the pain and other symptoms will quickly subside, but that doesn't mean the ulcer heals right away.

Literal

Medicine [object-を] start-taking [conditional-と], soon pain [etc.-など] [possessive-の] symptoms [topic-は] come-to-subside but, immediately ulcer [subject-が] heals reason is-not.

~てくる on とれる (subside) marks the change as coming toward the patient's experience. ~わけではありません denies the inference: just because symptoms go away doesn't mean healing is complete. 潰瘍 (ulcer) is a medical term. The sentence manages patient expectations — a common medical communication pattern.