( CNN ) -- Endurance swimmer Diana Nyad was stung by a sea creature for a second time Saturday night and was being treated by doctors , her team said in a blog post , leaving the continuation of her swim in question . The 62-year-old , in transit from Havana to Florida , was stung by some kind of presumed jellyfish , the blog said . `` Her face and eyes and the area around her eyes are affected . She is out of the water and aboard the transom of the Voyager where she is being treated by doctors . It will be up to Diana to decide whether or not to continue to the swim . '' The incident was another setback for the athlete , who was stung by Portuguese man o ' war earlier in the day . At 6:30 p.m. , Nyad was 49 miles from Havana . Having passed the 24-hour mark , she was entering a critical time in her quest to cover the 103 miles . `` Tonight , her second night in the open water , may be the most critical , '' the team wrote . `` Steve Munatones , the independent observer for the International Swim Federation who is accompanying the expedition , says that swimmers have a much better chance of success if they can make it through the second night . '' There was a bit of excitement early Saturday afternoon . An oceanic whitetip shark swam near Nyad , but a diver on her team faced it off and it meandered away . The swimmer improved her performance late Saturday morning after struggling to maintain her usual stroke rate , her support team said . Fortified by chicken soup , Nyad was making good progress until the Saturday evening incident . `` This afternoon -- it is stunning to actually witness -- Diana is swimming stronger and stronger , '' one post said . `` Her strokes are up to 50 per minute , she is eating pasta , gobbling bananas , bits of peanut butter sandwiches , along with high-carb & high calorie liquid concoctions . '' The going was rough before dawn Saturday , when Nyad had stopped her freestyle stroke and complained that she could n't breathe properly after getting stung . Doctors from the University of Miami gave the swimmer a shot to reduce inflammation , oxygen and other medication , the blog said , and after treading water for an hour Nyad said she felt better . Candace Hogan , a friend who has been on most of Nyad 's swims since 1978 , said she could recover and complete the 100-plus mile marathon , the blog said . The team initially said Nyad had likely been stung by a moon jellyfish but revised that to say it was the more troublesome Portuguese man o ' war . A National Institutes of Health report says an encounter with a Portuguese man o ' war can lead to `` significant systemic reactions '' but rarely death . While mild stings generally produce localized pain , severe ones can provoke symptoms ranging from headaches to seizures , delirium , coma and paralysis , as well as breathing problems , cramping and vomiting , the NIH says . Chief handler Bonnie Stoll said on Twitter that Nyad had been `` stung along both arms the side of her body and her face . '' Nyad had to clear herself of tentacles , change her swimsuit and put on a shirt for protection after the incident . Another member of Nyad 's support team said the way she handled the setback was a `` testament to her strength . '' `` It was scary , '' Stoll said . `` But Diana is happy that this happened early while she is still at her strongest . '' A safety diver who entered the water to help Nyad was also stung numerous times , her blog said . He received treatment back on one of the flotilla of boats accompanying her . Nyad began her swim just after 6 p.m. Friday from Havana 's Hemingway Marina . The former world champion swimmer expects the swim to take close to 60 hours , which would put her into Florida sometime Monday . Nyad last attempted this swim in early August and had to be pulled from the water after some 60 miles , and almost 29 hours of swimming . She blamed a shoulder injury she suffered early in the journey , and an 11-hour-long asthma attack . Her first Cuba-Florida attempt , back in 1978 , was brought to an end by strong currents and bad weather after almost 42 hours in the water , according to her website . CNN 's Matt Sloane and Shasta Darlington contributed to this report .
NEW : She is unsure whether she should continue the swim . A shark entered the swimming area , but swam away . This is her third attempt to swim the 100 miles from Cuba to Florida . Her first attempt , in 2004 , was cut short by bad weather and strong currents .